diff --git a/configure b/configure
index 55d0fbb654..be5211dd64 100755
--- a/configure
+++ b/configure
@@ -24062,7 +24062,7 @@ $as_echo "yes" >&6; }
                 GUI_TK_LIBRARY="${GUI_TK_LIBRARY} ${QT5_LIBS}"
                 if `pkg-config --variable qt_config Qt5Core | grep "reduce_relocations" >/dev/null`; then
                                         SAMPLES_CXXFLAGS="-fPIC $SAMPLES_CXXFLAGS"
-                    WXCONFIG_CXXFLAGS="-fPIC $WXCONFIG_CXXFLAGS $TOOLKIT_INCLUDE"
+                    WXCONFIG_CXXFLAGS="-fPIC $WXCONFIG_CXXFLAGS"
                 fi
 
 fi
diff --git a/configure.in b/configure.in
index a8bc2b94e3..231a04220d 100644
--- a/configure.in
+++ b/configure.in
@@ -3322,7 +3322,7 @@ libraries returned by 'pkg-config gtk+-2.0 --libs' or 'gtk-config
                 if `pkg-config --variable qt_config Qt5Core | grep "reduce_relocations" >/dev/null`; then
                     dnl build with position independent code if Qt needs it
                     SAMPLES_CXXFLAGS="-fPIC $SAMPLES_CXXFLAGS"
-                    WXCONFIG_CXXFLAGS="-fPIC $WXCONFIG_CXXFLAGS $TOOLKIT_INCLUDE"
+                    WXCONFIG_CXXFLAGS="-fPIC $WXCONFIG_CXXFLAGS"
                 fi
             ],
             [
diff --git a/include/wx/qt/accel.h b/include/wx/qt/accel.h
index be25cd13fd..a710f7f0ab 100644
--- a/include/wx/qt/accel.h
+++ b/include/wx/qt/accel.h
@@ -9,9 +9,6 @@
 #ifndef _WX_QT_ACCEL_H_
 #define _WX_QT_ACCEL_H_
 
-#include <QtCore/QList>
-#include <QtWidgets/QShortcut>
-
 /* wxQt accelerators implementation:
  *
  * Storing:
@@ -36,6 +33,9 @@
  * QShortcut. This handler will finally create and send the appropriate wx
  * event to the window. */
 
+class QShortcut;
+template < class T > class QList;
+
 class WXDLLIMPEXP_CORE wxAcceleratorTable : public wxObject
 {
 public:
@@ -43,7 +43,7 @@ public:
     wxAcceleratorTable(int n, const wxAcceleratorEntry entries[]);
 
     // Implementation
-    QList< QShortcut* > ConvertShortcutTable( QWidget *parent ) const;
+    QList < QShortcut* > *ConvertShortcutTable( QWidget *parent ) const;
 
     bool Ok() const { return IsOk(); }
     bool IsOk() const;
diff --git a/include/wx/qt/anybutton.h b/include/wx/qt/anybutton.h
index 975ffae6fe..1d07bc5b3b 100644
--- a/include/wx/qt/anybutton.h
+++ b/include/wx/qt/anybutton.h
@@ -9,7 +9,7 @@
 #ifndef _WX_QT_ANYBUTTON_H_
 #define _WX_QT_ANYBUTTON_H_
 
-#include <QtWidgets/QPushButton>
+class QPushButton;
 
 //-----------------------------------------------------------------------------
 // wxAnyButton
@@ -28,7 +28,7 @@ public:
     virtual void SetLabel( const wxString &label );
     virtual void DoSetBitmap(const wxBitmap& bitmap, State which);
 
-    virtual QPushButton *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 
 protected:
 
diff --git a/include/wx/qt/app.h b/include/wx/qt/app.h
index 55cee83781..80bda3a773 100644
--- a/include/wx/qt/app.h
+++ b/include/wx/qt/app.h
@@ -9,8 +9,7 @@
 #ifndef _WX_QT_APP_H_
 #define _WX_QT_APP_H_
 
-#include <QtWidgets/QApplication>
-
+class QApplication;
 class WXDLLIMPEXP_CORE wxApp : public wxAppBase
 {
 public:
diff --git a/include/wx/qt/brush.h b/include/wx/qt/brush.h
index a3f0fd0e6e..7dfe38ee22 100644
--- a/include/wx/qt/brush.h
+++ b/include/wx/qt/brush.h
@@ -8,8 +8,6 @@
 #ifndef _WX_QT_BRUSH_H_
 #define _WX_QT_BRUSH_H_
 
-#include <QtCore/Qt>
-
 class QBrush;
 
 class WXDLLIMPEXP_CORE wxBrush : public wxBrushBase
diff --git a/include/wx/qt/calctrl.h b/include/wx/qt/calctrl.h
index cf40ccc0c5..c8c7595750 100644
--- a/include/wx/qt/calctrl.h
+++ b/include/wx/qt/calctrl.h
@@ -11,7 +11,7 @@
 #define _WX_QT_CALCTRL_H_
 
 #include "wx/calctrl.h"
-#include <QtWidgets/QCalendarWidget>
+class QCalendarWidget;
 
 class WXDLLIMPEXP_ADV wxCalendarCtrl : public wxCalendarCtrlBase
 {
@@ -70,7 +70,7 @@ public:
 
     using wxCalendarCtrlBase::GenerateAllChangeEvents;
 
-    virtual QCalendarWidget *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 
 protected:
     virtual void RefreshHolidays();
diff --git a/include/wx/qt/checkbox.h b/include/wx/qt/checkbox.h
index adf2c2ac6f..6bb328de70 100644
--- a/include/wx/qt/checkbox.h
+++ b/include/wx/qt/checkbox.h
@@ -8,7 +8,7 @@
 #ifndef _WX_QT_CHECKBOX_H_
 #define _WX_QT_CHECKBOX_H_
 
-#include <QtWidgets/QCheckBox>
+class QCheckBox;
 
 class WXDLLIMPEXP_CORE wxCheckBox : public wxCheckBoxBase
 {
@@ -32,7 +32,7 @@ public:
     virtual void SetValue(bool value);
     virtual bool GetValue() const;
 
-    virtual QCheckBox *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 
 protected:
     virtual void DoSet3StateValue(wxCheckBoxState state);
diff --git a/include/wx/qt/choice.h b/include/wx/qt/choice.h
index 8ab1811879..06602b9b68 100644
--- a/include/wx/qt/choice.h
+++ b/include/wx/qt/choice.h
@@ -8,7 +8,7 @@
 #ifndef _WX_QT_CHOICE_H_
 #define _WX_QT_CHOICE_H_
 
-#include <QtWidgets/QComboBox>
+class QComboBox;
 
 class WXDLLIMPEXP_CORE wxChoice : public wxChoiceBase
 {
@@ -56,7 +56,7 @@ public:
     virtual void SetSelection(int n);
     virtual int GetSelection() const;
 
-    virtual QComboBox *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 
 protected:
     virtual int DoInsertItems(const wxArrayStringsAdapter & items,
diff --git a/include/wx/qt/colordlg.h b/include/wx/qt/colordlg.h
index 3e65349d40..fec19d7d94 100644
--- a/include/wx/qt/colordlg.h
+++ b/include/wx/qt/colordlg.h
@@ -10,7 +10,7 @@
 
 #include "wx/dialog.h"
 
-#include <QtWidgets/QColorDialog>
+class QColorDialog;
 
 class WXDLLIMPEXP_CORE wxColourDialog : public wxDialog
 {
@@ -23,9 +23,8 @@ public:
 
     wxColourData &GetColourData();
 
-    QColorDialog *GetHandle() const { return static_cast<QColorDialog *>(m_qtWindow); }
-
 private:
+    QColorDialog *GetQColorDialog() const;
 
     wxColourData m_data;
 };
diff --git a/include/wx/qt/combobox.h b/include/wx/qt/combobox.h
index 3b0169f9c6..1f80df5b37 100644
--- a/include/wx/qt/combobox.h
+++ b/include/wx/qt/combobox.h
@@ -9,7 +9,7 @@
 #define _WX_QT_COMBOBOX_H_
 
 #include "wx/choice.h"
-#include <QtWidgets/QComboBox>
+class QComboBox;
 
 class WXDLLIMPEXP_CORE wxComboBox : public wxChoice, public wxTextEntry
 {
diff --git a/include/wx/qt/cursor.h b/include/wx/qt/cursor.h
index 47320195dc..b57f770a6f 100644
--- a/include/wx/qt/cursor.h
+++ b/include/wx/qt/cursor.h
@@ -10,7 +10,7 @@
 
 #include "wx/image.h"
 
-#include <QtGui/QCursor>
+class QCursor;
 
 class WXDLLIMPEXP_CORE wxCursor : public wxCursorBase
 {
@@ -36,7 +36,8 @@ protected:
     void InitFromImage( const wxImage & image );
 #endif
 
-protected:
+private:
+    void Init();
     virtual wxGDIRefData *CreateGDIRefData() const;
     virtual wxGDIRefData *CloneGDIRefData(const wxGDIRefData *data) const;
 
diff --git a/include/wx/qt/dataform.h b/include/wx/qt/dataform.h
index 612903a881..b6f5c307bf 100644
--- a/include/wx/qt/dataform.h
+++ b/include/wx/qt/dataform.h
@@ -8,6 +8,8 @@
 #ifndef _WX_QT_DATAFORM_H_
 #define _WX_QT_DATAFORM_H_
 
+class QString;
+
 class WXDLLIMPEXP_CORE wxDataFormat
 {
 public:
@@ -33,7 +35,7 @@ public:
     wxDataFormatId GetType() const;
     void SetType( wxDataFormatId type );
 
-    QString m_MimeType;
+    wxString m_MimeType;
 };
 
 #endif // _WX_QT_DATAFORM_H_
diff --git a/include/wx/qt/dataobj.h b/include/wx/qt/dataobj.h
index 8ccc1908e4..002de9c2a0 100644
--- a/include/wx/qt/dataobj.h
+++ b/include/wx/qt/dataobj.h
@@ -8,12 +8,13 @@
 #ifndef _WX_QT_DATAOBJ_H_
 #define _WX_QT_DATAOBJ_H_
 
-#include <QMimeData>
+class QMimeData;
 
 class WXDLLIMPEXP_CORE wxDataObject : public wxDataObjectBase
 {
 public:
-    wxDataObject() {}
+    wxDataObject();
+    ~wxDataObject();
     
     virtual bool IsSupportedFormat(const wxDataFormat& format, Direction dir) const;
     virtual wxDataFormat GetPreferredFormat(Direction dir = Get) const;
@@ -24,7 +25,7 @@ public:
     virtual bool SetData(const wxDataFormat& format, size_t len, const void * buf);
 
 private:
-    QMimeData m_qtMimeData; // to handle formats that have no helper classes
+    QMimeData *m_qtMimeData; // to handle formats that have no helper classes
 };
 
 #endif // _WX_QT_DATAOBJ_H_
diff --git a/include/wx/qt/dc.h b/include/wx/qt/dc.h
index adb0fac3e2..5a4ece366c 100644
--- a/include/wx/qt/dc.h
+++ b/include/wx/qt/dc.h
@@ -8,8 +8,7 @@
 #ifndef _WX_QT_DC_H_
 #define _WX_QT_DC_H_
 
-#include <QtGui/QPainter>
-
+class QPainter;
 class QImage;
 
 class WXDLLIMPEXP_FWD_CORE wxRegion;
@@ -125,8 +124,8 @@ private:
         wxQtINVERT
     };
     wxQtRasterColourOp m_rasterColourOp;
-    QColor m_qtPenColor;
-    QColor m_qtBrushColor;
+    QColor *m_qtPenColor;
+    QColor *m_qtBrushColor;
     void ApplyRasterColourOp();
     
 };
diff --git a/include/wx/qt/dialog.h b/include/wx/qt/dialog.h
index 3a857309c8..5ae3b04a33 100644
--- a/include/wx/qt/dialog.h
+++ b/include/wx/qt/dialog.h
@@ -9,7 +9,7 @@
 #define _WX_QT_DIALOG_H_
 
 #include "wx/dialog.h"
-#include <QtWidgets/QDialog>
+class QDialog;
 
 class WXDLLIMPEXP_CORE wxDialog : public wxDialogBase
 {
@@ -35,7 +35,7 @@ public:
     virtual void EndModal(int retCode);
     virtual bool IsModal() const;
 
-    virtual QDialog *GetHandle() const;
+    QDialog *GetDialogHandle() const;
 
 private:
 
diff --git a/include/wx/qt/dirdlg.h b/include/wx/qt/dirdlg.h
index f7bc38a3f5..17d8dfc8fb 100644
--- a/include/wx/qt/dirdlg.h
+++ b/include/wx/qt/dirdlg.h
@@ -8,7 +8,7 @@
 #ifndef _WX_QT_DIRDLG_H_
 #define _WX_QT_DIRDLG_H_
 
-#include <QtWidgets/QFileDialog>
+class QFileDialog;
 
 class WXDLLIMPEXP_CORE wxDirDialog : public wxDirDialogBase
 {
@@ -36,10 +36,10 @@ public:     // overrides from wxGenericDirDialog
     wxString GetPath() const wxOVERRIDE;
     void SetPath(const wxString& path) wxOVERRIDE;
 
-    virtual QFileDialog *GetHandle() const;
-
 private:
 
+    virtual QFileDialog *GetQFileDialog() const;
+
     wxDECLARE_DYNAMIC_CLASS(wxDirDialog);
 };
 
diff --git a/include/wx/qt/evtloop.h b/include/wx/qt/evtloop.h
index d46609f7a8..6034a808a7 100644
--- a/include/wx/qt/evtloop.h
+++ b/include/wx/qt/evtloop.h
@@ -8,7 +8,7 @@
 #ifndef _WX_QT_EVTLOOP_H_
 #define _WX_QT_EVTLOOP_H_
 
-#include <QtCore/QTimer>
+class QTimer;
 
 class WXDLLIMPEXP_BASE wxQtEventLoopBase : public wxEventLoopBase
 {
@@ -58,21 +58,4 @@ public:
 
 #endif // wxUSE_GUI
 
-
-class wxQtEventLoopBase;
-
-class wxQtIdleTimer : public QTimer
-{
-
-public:
-    wxQtIdleTimer( wxQtEventLoopBase *eventLoop );
-    virtual bool eventFilter( QObject * watched, QEvent * event  );
-
-private:
-    void idle();
-
-private:
-    wxQtEventLoopBase *m_eventLoop;
-};
-
 #endif // _WX_QT_EVTLOOP_H_
diff --git a/include/wx/qt/filedlg.h b/include/wx/qt/filedlg.h
index 47ce43fc96..4c907aea83 100644
--- a/include/wx/qt/filedlg.h
+++ b/include/wx/qt/filedlg.h
@@ -8,7 +8,7 @@
 #ifndef _WX_QT_FILEDLG_H_
 #define _WX_QT_FILEDLG_H_
 
-#include <QtWidgets/QFileDialog>
+class QFileDialog;
 
 class WXDLLIMPEXP_CORE wxFileDialog : public wxFileDialogBase
 {
@@ -48,7 +48,7 @@ public:
 
     virtual bool SupportsExtraControl() const wxOVERRIDE { return true; }
 
-    virtual QFileDialog *GetHandle() const;
+    virtual QFileDialog *GetQFileDialog() const;
 
 private:
 
diff --git a/include/wx/qt/fontdlg.h b/include/wx/qt/fontdlg.h
index b1d63464cc..df739d3852 100644
--- a/include/wx/qt/fontdlg.h
+++ b/include/wx/qt/fontdlg.h
@@ -8,7 +8,7 @@
 #ifndef _WX_QT_FONTDLG_H_
 #define _WX_QT_FONTDLG_H_
 
-#include <QtWidgets/QFontDialog>
+class QFontDialog;
 
 class WXDLLIMPEXP_CORE wxFontDialog : public wxFontDialogBase
 {
@@ -17,8 +17,6 @@ public:
     wxFontDialog(wxWindow *parent) { Create(parent); }
     wxFontDialog(wxWindow *parent, const wxFontData& data) { Create(parent, data); }
     
-    virtual QFontDialog *GetHandle() const { return static_cast<QFontDialog *>(m_qtWindow); }
-
 protected:
     bool DoCreate(wxWindow *parent);
     
diff --git a/include/wx/qt/frame.h b/include/wx/qt/frame.h
index aaf0541774..35a7f39aaa 100644
--- a/include/wx/qt/frame.h
+++ b/include/wx/qt/frame.h
@@ -12,8 +12,9 @@
 #define _WX_QT_FRAME_H_
 
 #include "wx/frame.h"
-#include <QtWidgets/QMainWindow>
-#include <QtWidgets/QScrollArea>
+
+class QMainWindow;
+class QScrollArea;
 
 class WXDLLIMPEXP_CORE wxFrame : public wxFrameBase
 {
@@ -45,12 +46,8 @@ public:
     virtual void AddChild( wxWindowBase *child );
     virtual void RemoveChild( wxWindowBase *child );
 
-    virtual QMainWindow *GetHandle() const
-    {
-        return static_cast<QMainWindow*>(m_qtWindow);
-    }
-
-    virtual QAbstractScrollArea *QtGetScrollBarsContainer() const;
+    QMainWindow *GetQMainWindow() const;
+    virtual QScrollArea *QtGetScrollBarsContainer() const;
 
 protected:
     virtual void DoGetClientSize(int *width, int *height) const;
diff --git a/include/wx/qt/gauge.h b/include/wx/qt/gauge.h
index 4a21c47f36..fc59debbe8 100644
--- a/include/wx/qt/gauge.h
+++ b/include/wx/qt/gauge.h
@@ -8,7 +8,7 @@
 #ifndef _WX_QT_GAUGE_H_
 #define _WX_QT_GAUGE_H_
 
-#include <QtWidgets/QProgressBar>
+class QProgressBar;
 
 class WXDLLIMPEXP_CORE wxGauge : public wxGaugeBase
 {
@@ -33,7 +33,7 @@ public:
                 const wxValidator& validator = wxDefaultValidator,
                 const wxString& name = wxGaugeNameStr);
 
-    virtual QProgressBar *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 
     // set/get the control range
     virtual void SetRange(int range);
diff --git a/include/wx/qt/glcanvas.h b/include/wx/qt/glcanvas.h
index 13cce8a2ea..a67efa09b0 100644
--- a/include/wx/qt/glcanvas.h
+++ b/include/wx/qt/glcanvas.h
@@ -8,7 +8,11 @@
 #ifndef _WX_GLCANVAS_H_
 #define _WX_GLCANVAS_H_
 
-#include <QtOpenGL/QGLWidget>
+#include <GL/gl.h>
+
+class QGLWidget;
+class QGLContext;
+class QGLFormat;
 
 class WXDLLIMPEXP_GL wxGLContext : public wxGLContextBase
 {
@@ -54,8 +58,6 @@ public:
 
     static bool ConvertWXAttrsToQtGL(const int *wxattrs, QGLFormat &format);
 
-    virtual QGLWidget *GetHandle() const { return static_cast<QGLWidget *>(m_qtWindow); }
-
 private:
 
 //    wxDECLARE_EVENT_TABLE();
diff --git a/include/wx/qt/listbox.h b/include/wx/qt/listbox.h
index 59e5822dad..ce67508169 100644
--- a/include/wx/qt/listbox.h
+++ b/include/wx/qt/listbox.h
@@ -8,7 +8,9 @@
 #ifndef _WX_QT_LISTBOX_H_
 #define _WX_QT_LISTBOX_H_
 
-#include <QtWidgets/QListWidget>
+class QListWidget;
+class QModelIndex;
+class QScrollArea;
 
 class WXDLLIMPEXP_CORE wxListBox : public wxListBoxBase
 {
@@ -57,7 +59,7 @@ public:
     virtual void SetSelection(int n);
     virtual int GetSelection() const;
 
-    virtual QListWidget *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 
     void QtSendEvent(wxEventType evtType, const QModelIndex &index, bool selected);
 
diff --git a/include/wx/qt/listctrl.h b/include/wx/qt/listctrl.h
index 3b08104dcc..17637de752 100644
--- a/include/wx/qt/listctrl.h
+++ b/include/wx/qt/listctrl.h
@@ -9,7 +9,9 @@
 #define _WX_QT_LISTCTRL_H_
 
 #include "wx/textctrl.h"
-#include <QtWidgets/QTreeWidget>
+
+class QTreeWidget;
+class QTreeWidgetItem;
 
 class WXDLLIMPEXP_FWD_CORE wxImageList;
 
@@ -284,7 +286,7 @@ public:
         return OnGetItemAttr(item);
     }
 
-    virtual QTreeWidget *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 
 protected:
     void Init();
diff --git a/include/wx/qt/menu.h b/include/wx/qt/menu.h
index b45f3ca61b..b8d5abca52 100644
--- a/include/wx/qt/menu.h
+++ b/include/wx/qt/menu.h
@@ -8,8 +8,8 @@
 #ifndef _WX_QT_MENU_H_
 #define _WX_QT_MENU_H_
 
-#include <QtWidgets/QMenu>
-#include <QtWidgets/QMenuBar>
+class QMenu;
+class QMenuBar;
 
 class WXDLLIMPEXP_CORE wxMenu : public wxMenuBase
 {
@@ -48,7 +48,8 @@ public:
     virtual void SetMenuLabel(size_t pos, const wxString& label);
     virtual wxString GetMenuLabel(size_t pos) const;
 
-    virtual QMenuBar *GetHandle() const;
+    QMenuBar *GetQMenuBar() const { return m_qtMenuBar; }
+    virtual QWidget *GetHandle() const;
 
     virtual void Attach(wxFrame *frame);
     virtual void Detach();
diff --git a/include/wx/qt/menuitem.h b/include/wx/qt/menuitem.h
index 0a07c55f02..158007fc4e 100644
--- a/include/wx/qt/menuitem.h
+++ b/include/wx/qt/menuitem.h
@@ -9,7 +9,7 @@
 #define _WX_QT_MENUITEM_H_
 
 #include "wx/menuitem.h"
-#include <QtWidgets/QAction>
+class QAction;
 
 class WXDLLIMPEXP_FWD_CORE wxBitmap;
 class WXDLLIMPEXP_FWD_CORE wxMenu;
diff --git a/include/wx/qt/msgdlg.h b/include/wx/qt/msgdlg.h
index 447dd60522..6f1acdc16a 100644
--- a/include/wx/qt/msgdlg.h
+++ b/include/wx/qt/msgdlg.h
@@ -10,7 +10,7 @@
 
 #include "wx/msgdlg.h"
 
-#include <QtWidgets/QMessageBox>
+class QMessageBox;
 
 class WXDLLIMPEXP_CORE wxMessageDialog : public wxMessageDialogBase
 {
@@ -23,9 +23,6 @@ public:
 
     // Reimplemented to translate return codes from Qt to wx
     virtual int ShowModal();
-    
-    virtual QMessageBox *GetHandle() const;
-
 };
 
 #endif // _WX_QT_MSGDLG_H_
diff --git a/include/wx/qt/notebook.h b/include/wx/qt/notebook.h
index c62fb4e859..288d0d9a7f 100644
--- a/include/wx/qt/notebook.h
+++ b/include/wx/qt/notebook.h
@@ -8,7 +8,7 @@
 #ifndef _WX_QT_NOTEBOOK_H_
 #define _WX_QT_NOTEBOOK_H_
 
-#include <QtWidgets/QTabWidget>
+class QTabWidget;
 
 class WXDLLIMPEXP_CORE wxNotebook : public wxNotebookBase
 {
@@ -45,7 +45,7 @@ public:
     int SetSelection(size_t nPage) { return DoSetSelection(nPage, SetSelection_SendEvent); }
     int ChangeSelection(size_t nPage) { return DoSetSelection(nPage); }
 
-    virtual QTabWidget *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 
 protected:
     virtual wxWindow *DoRemovePage(size_t page);
diff --git a/include/wx/qt/pen.h b/include/wx/qt/pen.h
index bbaad08379..42c57a5304 100644
--- a/include/wx/qt/pen.h
+++ b/include/wx/qt/pen.h
@@ -8,8 +8,6 @@
 #ifndef _WX_QT_PEN_H_
 #define _WX_QT_PEN_H_
 
-#include <QtCore/Qt>
-
 class QPen;
 
 class WXDLLIMPEXP_CORE wxPen : public wxPenBase
diff --git a/include/wx/qt/timer.h b/include/wx/qt/private/timer.h
similarity index 98%
rename from include/wx/qt/timer.h
rename to include/wx/qt/private/timer.h
index cfb875f8d9..21ce2f79d6 100644
--- a/include/wx/qt/timer.h
+++ b/include/wx/qt/private/timer.h
@@ -10,14 +10,14 @@
 
 #if wxUSE_TIMER
 
-#include "wx/private/timer.h"
-
 #include <QtCore/QObject>
+#include "wx/private/timer.h"
 
 //-----------------------------------------------------------------------------
 // wxTimer
 //-----------------------------------------------------------------------------
 
+class QTimerEvent;
 class WXDLLIMPEXP_CORE wxQtTimerImpl : public wxTimerImpl, QObject
 {
 public:
diff --git a/include/wx/qt/private/winevent.h b/include/wx/qt/private/winevent.h
index cbda1cc2a2..40ea85e417 100644
--- a/include/wx/qt/private/winevent.h
+++ b/include/wx/qt/private/winevent.h
@@ -11,13 +11,15 @@
 #ifndef _WX_QT_EVENTSIGNALFORWARDER_H_
 #define _WX_QT_EVENTSIGNALFORWARDER_H_
 
+#include <QtCore/QEvent>
+#include <QtGui/QCloseEvent>
+
 #include "wx/log.h"
 #include "wx/window.h"
 #include "wx/qt/private/converter.h"
 #include "wx/qt/private/utils.h"
 
-#include <QtCore/QEvent>
-#include <QtGui/QPaintEvent>
+class QPaintEvent;
 
 template< typename Handler >
 class wxQtSignalHandler
diff --git a/include/wx/qt/radiobox.h b/include/wx/qt/radiobox.h
index 62ea5a50cc..f858a576f6 100644
--- a/include/wx/qt/radiobox.h
+++ b/include/wx/qt/radiobox.h
@@ -8,9 +8,9 @@
 #ifndef _WX_QT_RADIOBOX_H_
 #define _WX_QT_RADIOBOX_H_
 
-#include <QtWidgets/QGroupBox>
-#include <QtWidgets/QButtonGroup>
-#include <QtWidgets/QVBoxLayout>
+class QGroupBox;
+class QButtonGroup;
+class QBoxLayout;
 
 class WXDLLIMPEXP_CORE wxRadioBox : public wxControl, public wxRadioBoxBase
 {
@@ -77,7 +77,7 @@ public:
     virtual void SetSelection(int n);
     virtual int GetSelection() const;
 
-    virtual QGroupBox *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 
 private:
     // The 'visual' group box:
diff --git a/include/wx/qt/radiobut.h b/include/wx/qt/radiobut.h
index 164a0c3f4e..6679be6d04 100644
--- a/include/wx/qt/radiobut.h
+++ b/include/wx/qt/radiobut.h
@@ -8,7 +8,7 @@
 #ifndef _WX_QT_RADIOBUT_H_
 #define _WX_QT_RADIOBUT_H_
 
-#include <QtWidgets/QRadioButton>
+class QRadioButton;
 
 class WXDLLIMPEXP_CORE wxRadioButton : public wxControl
 {
@@ -35,7 +35,7 @@ public:
     virtual void SetValue(bool value);
     virtual bool GetValue() const;
 
-    virtual QRadioButton *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 
 protected:
 
diff --git a/include/wx/qt/region.h b/include/wx/qt/region.h
index c5ffb699a3..17840ead77 100644
--- a/include/wx/qt/region.h
+++ b/include/wx/qt/region.h
@@ -9,7 +9,9 @@
 #ifndef _WX_QT_REGION_H_
 #define _WX_QT_REGION_H_
 
-#include <QtGui/QRegion>
+class QRegion;
+class QRect;
+template<class T> class QVector;
 
 class WXDLLIMPEXP_CORE wxRegion : public wxRegionBase
 {
@@ -25,7 +27,7 @@ public:
     virtual bool IsEmpty() const;
     virtual void Clear();
 
-    virtual QRegion GetHandle() const;
+    virtual const QRegion &GetHandle() const;
     virtual void QtSetRegion(QRegion region); // Hangs on to this region
 
 protected:
@@ -45,8 +47,6 @@ protected:
     virtual bool DoIntersect(const wxRegion& region);
     virtual bool DoSubtract(const wxRegion& region);
     virtual bool DoXor(const wxRegion& region);
-    
-private:
 };
 
 
@@ -79,7 +79,7 @@ public:
     wxRect GetRect() const;
     
 private:
-    QVector< QRect > *m_qtRects;
+    QVector < QRect > *m_qtRects;
     int m_pos;
 };
 
diff --git a/include/wx/qt/scrolbar.h b/include/wx/qt/scrolbar.h
index 2efa3dde30..e1ea3ebe4b 100644
--- a/include/wx/qt/scrolbar.h
+++ b/include/wx/qt/scrolbar.h
@@ -10,7 +10,7 @@
 
 #include "wx/scrolbar.h"
 
-#include <QtWidgets/QScrollBar>
+class QScrollBar;
 
 class WXDLLIMPEXP_FWD_CORE wxQtScrollBar;
 
@@ -42,7 +42,8 @@ public:
                               int range, int pageSize,
                               bool refresh = true);
 
-    virtual QScrollBar* GetHandle() const;
+    QScrollBar *GetQScrollBar() const { return m_qtScrollBar; }
+    QWidget *GetHandle() const;
 
 private:
     QScrollBar *m_qtScrollBar;
diff --git a/include/wx/qt/slider.h b/include/wx/qt/slider.h
index 1c103d094c..0a183f84b1 100644
--- a/include/wx/qt/slider.h
+++ b/include/wx/qt/slider.h
@@ -8,7 +8,7 @@
 #ifndef _WX_QT_SLIDER_H_
 #define _WX_QT_SLIDER_H_
 
-#include <QtWidgets/QSlider>
+class QSlider;
 
 class WXDLLIMPEXP_CORE wxSlider : public wxSliderBase
 {
@@ -50,7 +50,7 @@ public:
     virtual void SetThumbLength(int lenPixels);
     virtual int GetThumbLength() const;
 
-    virtual QSlider *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 
 private:
     QSlider *m_qtSlider;
diff --git a/include/wx/qt/spinbutt.h b/include/wx/qt/spinbutt.h
index 96a3294756..6df89572e4 100644
--- a/include/wx/qt/spinbutt.h
+++ b/include/wx/qt/spinbutt.h
@@ -9,7 +9,7 @@
 #define _WX_QT_SPINBUTT_H_
 
 #include "wx/spinbutt.h"
-#include <QtWidgets/QSpinBox>
+class QSpinBox;
 
 class WXDLLIMPEXP_CORE wxSpinButton : public wxSpinButtonBase
 {
@@ -32,7 +32,7 @@ public:
     virtual int GetValue() const;
     virtual void SetValue(int val);
 
-    virtual QSpinBox *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 
 private:
     QSpinBox *m_qtSpinBox;
diff --git a/include/wx/qt/spinctrl.h b/include/wx/qt/spinctrl.h
index 756272b29a..f6cf3df2d1 100644
--- a/include/wx/qt/spinctrl.h
+++ b/include/wx/qt/spinctrl.h
@@ -8,8 +8,8 @@
 #ifndef _WX_QT_SPINCTRL_H_
 #define _WX_QT_SPINCTRL_H_
 
-#include <QtWidgets/QSpinBox>
-#include <QtWidgets/QDoubleSpinBox>
+class QSpinBox;
+class QDoubleSpinBox;
 
 // Take advantage of the Qt compile time polymorphy and use a template to avoid
 // copy&paste code for the usage of QSpinBox/QDoubleSpinBox.
@@ -45,7 +45,7 @@ public:
     T GetMax() const;
     T GetIncrement() const;
 
-    virtual Widget *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 
 protected:
     Widget *m_qtSpinBox;
diff --git a/include/wx/qt/statbmp.h b/include/wx/qt/statbmp.h
index a4b87687d6..a61fb5e8fc 100644
--- a/include/wx/qt/statbmp.h
+++ b/include/wx/qt/statbmp.h
@@ -8,7 +8,7 @@
 #ifndef _WX_QT_STATBMP_H_
 #define _WX_QT_STATBMP_H_
 
-#include <QtWidgets/QLabel>
+class QLabel;
 
 class WXDLLIMPEXP_CORE wxStaticBitmap : public wxStaticBitmapBase
 {
@@ -35,7 +35,7 @@ public:
     virtual wxBitmap GetBitmap() const;
     virtual wxIcon GetIcon() const;
 
-    virtual QLabel *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 protected:
 
 private:
diff --git a/include/wx/qt/statbox.h b/include/wx/qt/statbox.h
index 4259f74ec1..186146b242 100644
--- a/include/wx/qt/statbox.h
+++ b/include/wx/qt/statbox.h
@@ -8,7 +8,7 @@
 #ifndef _WX_QT_STATBOX_H_
 #define _WX_QT_STATBOX_H_
 
-#include <QtWidgets/QGroupBox>
+class QGroupBox;
 
 class WXDLLIMPEXP_CORE wxStaticBox : public wxStaticBoxBase
 {
@@ -31,7 +31,7 @@ public:
 
     virtual void GetBordersForSizer(int *borderTop, int *borderOther) const;
 
-    virtual QGroupBox *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 
 protected:
 
diff --git a/include/wx/qt/statline.h b/include/wx/qt/statline.h
index d65706b683..aca385e5ec 100644
--- a/include/wx/qt/statline.h
+++ b/include/wx/qt/statline.h
@@ -8,7 +8,7 @@
 #ifndef _WX_QT_STATLINE_H_
 #define _WX_QT_STATLINE_H_
 
-#include <QtWidgets/QFrame>
+class QFrame;
 
 class WXDLLIMPEXP_CORE wxStaticLine : public wxStaticLineBase
 {
@@ -29,7 +29,7 @@ public:
                  long style = wxLI_HORIZONTAL,
                  const wxString &name = wxStaticLineNameStr );
 
-    virtual QFrame *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 
 private:
     QFrame *m_qtFrame;
diff --git a/include/wx/qt/stattext.h b/include/wx/qt/stattext.h
index 0aae47e778..36f8628aae 100644
--- a/include/wx/qt/stattext.h
+++ b/include/wx/qt/stattext.h
@@ -8,7 +8,7 @@
 #ifndef _WX_QT_STATTEXT_H_
 #define _WX_QT_STATTEXT_H_
 
-#include <QtWidgets/QLabel>
+class QLabel;
 
 class WXDLLIMPEXP_CORE wxStaticText : public wxStaticTextBase
 {
@@ -32,7 +32,8 @@ public:
 
     void SetLabel(const wxString& label);
 
-    QLabel *GetHandle() const;
+    virtual QWidget *GetHandle() const;
+
 private:
     QLabel *m_qtLabel;
 
diff --git a/include/wx/qt/statusbar.h b/include/wx/qt/statusbar.h
index 233e506efd..0609d4b044 100644
--- a/include/wx/qt/statusbar.h
+++ b/include/wx/qt/statusbar.h
@@ -10,13 +10,15 @@
 
 #include "wx/statusbr.h"
 
-#include <QtWidgets/QLabel>
-#include <QtWidgets/QStatusBar>
+class QLabel;
+class QStatusBar;
+
+template < class T > class QList;
 
 class WXDLLIMPEXP_CORE wxStatusBar : public wxStatusBarBase
 {
 public:
-    wxStatusBar() {}
+    wxStatusBar();
     wxStatusBar(wxWindow *parent, wxWindowID winid = wxID_ANY,
                 long style = wxSTB_DEFAULT_STYLE,
                 const wxString& name = wxStatusBarNameStr);
@@ -32,8 +34,9 @@ public:
     virtual void Refresh( bool eraseBackground = true,
                           const wxRect *rect = (const wxRect *) NULL );
 
-    virtual QStatusBar *GetHandle() const;
-
+    QStatusBar *GetQStatusBar() const { return m_qtStatusBar; }
+    QWidget *GetHandle() const;
+    
 protected:
     virtual void DoUpdateStatusText(int number);
 
@@ -42,7 +45,7 @@ private:
     void UpdateFields();
 
     QStatusBar *m_qtStatusBar;
-    QList< QLabel* > m_qtPanes;
+    QList< QLabel* > *m_qtPanes;
 
     wxDECLARE_DYNAMIC_CLASS(wxStatusBar);
 };
diff --git a/include/wx/qt/taskbar.h b/include/wx/qt/taskbar.h
index 6a29f93749..5de2f084b8 100644
--- a/include/wx/qt/taskbar.h
+++ b/include/wx/qt/taskbar.h
@@ -8,12 +8,13 @@
 #ifndef _WX_QT_TASKBAR_H_
 #define _WX_QT_TASKBAR_H_
 
-#include <QtWidgets/QSystemTrayIcon>
+class QSystemTrayIcon;
 
 class WXDLLIMPEXP_CORE wxTaskBarIcon : public wxTaskBarIconBase
 {
 public:
     wxTaskBarIcon(wxTaskBarIconType iconType = wxTBI_DEFAULT_TYPE);
+    virtual ~wxTaskBarIcon();
 
     // Accessors
     bool IsOk() const { return false; }
@@ -26,7 +27,7 @@ public:
     virtual bool PopupMenu(wxMenu *menu);
 
 private:
-    QSystemTrayIcon m_qtSystemTrayIcon;
+    QSystemTrayIcon *m_qtSystemTrayIcon;
 
     wxDECLARE_DYNAMIC_CLASS_NO_COPY(wxTaskBarIcon);
 };
diff --git a/include/wx/qt/textctrl.h b/include/wx/qt/textctrl.h
index 864165c88c..fda210583c 100644
--- a/include/wx/qt/textctrl.h
+++ b/include/wx/qt/textctrl.h
@@ -8,8 +8,9 @@
 #ifndef _WX_QT_TEXTCTRL_H_
 #define _WX_QT_TEXTCTRL_H_
 
-#include <QtWidgets/QLineEdit>
-#include <QtWidgets/QTextEdit>
+class QLineEdit;
+class QTextEdit;
+class QScrollArea;
 
 class WXDLLIMPEXP_CORE wxTextCtrl : public wxTextCtrlBase
 {
diff --git a/include/wx/qt/tglbtn.h b/include/wx/qt/tglbtn.h
index 1aee755854..3eaa69e044 100644
--- a/include/wx/qt/tglbtn.h
+++ b/include/wx/qt/tglbtn.h
@@ -36,7 +36,7 @@ public:
     virtual void SetValue(bool state);
     virtual bool GetValue() const;
 
-    virtual QPushButton *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 
 private:
     wxDECLARE_DYNAMIC_CLASS(wxBitmapToggleButton);
@@ -69,7 +69,7 @@ public:
     virtual void SetValue(bool state);
     virtual bool GetValue() const;
 
-    virtual QPushButton *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 
 private:
 
diff --git a/include/wx/qt/toolbar.h b/include/wx/qt/toolbar.h
index 0c9e4506f3..10639b6aac 100644
--- a/include/wx/qt/toolbar.h
+++ b/include/wx/qt/toolbar.h
@@ -5,7 +5,7 @@
 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 
-#include <QtWidgets/QToolBar>
+class QToolBar;
 
 #ifndef _WX_QT_TOOLBAR_H_
 #define _WX_QT_TOOLBAR_H_
@@ -41,7 +41,7 @@ public:
                 const wxString& name = wxToolBarNameStr);
 
     virtual wxToolBarToolBase *FindToolForPosition(wxCoord x, wxCoord y) const;
-    virtual QToolBar *GetHandle() const;
+    virtual QToolBar *GetQToolBar() const { return m_qtToolBar; }
 
     virtual void SetWindowStyleFlag( long style );
     virtual bool Realize() wxOVERRIDE;
@@ -57,7 +57,8 @@ public:
 
     virtual wxToolBarToolBase *CreateTool(wxControl *control,
                                           const wxString& label);
-
+    QWidget *GetHandle() const;
+    
 protected:
 
     QActionGroup* GetActionGroup(size_t pos);
@@ -68,7 +69,7 @@ protected:
     virtual void DoSetToggle(wxToolBarToolBase *tool, bool toggle);
 
 private:
-    Qt::ToolButtonStyle GetButtonStyle();
+    long GetButtonStyle();
 
     QToolBar *m_qtToolBar;
 
diff --git a/include/wx/qt/treectrl.h b/include/wx/qt/treectrl.h
index af832c522f..2abf2e17f4 100644
--- a/include/wx/qt/treectrl.h
+++ b/include/wx/qt/treectrl.h
@@ -8,7 +8,7 @@
 #ifndef _WX_QT_TREECTRL_H_
 #define _WX_QT_TREECTRL_H_
 
-#include <QtWidgets/QTreeWidget>
+class QTreeWidget;
 
 class WXDLLIMPEXP_CORE wxTreeCtrl : public wxTreeCtrlBase
 {
@@ -112,7 +112,7 @@ public:
 
     virtual bool GetBoundingRect(const wxTreeItemId& item, wxRect& rect, bool textOnly = false) const;
 
-    virtual QTreeWidget *GetHandle() const;
+    virtual QWidget *GetHandle() const;
 
 protected:
     virtual int DoGetItemState(const wxTreeItemId& item) const;
diff --git a/include/wx/qt/window.h b/include/wx/qt/window.h
index 2689f51303..76f87791f4 100644
--- a/include/wx/qt/window.h
+++ b/include/wx/qt/window.h
@@ -9,8 +9,27 @@
 #ifndef _WX_QT_WINDOW_H_
 #define _WX_QT_WINDOW_H_
 
-#include <QtWidgets/QWidget>
-#include <QtWidgets/QScrollArea>
+#include <list>
+
+class QWidget;
+class QScrollWindow;
+class QAbstractScrollArea;
+class QScrollArea;
+class QPicture;
+class QPainter;
+
+class QPaintEvent;
+class QResizeEvent;
+class QWheelEvent;
+class QKeyEvent;
+class QMouseEvent;
+class QEvent;
+class QMoveEvent;
+class QEvent;
+class QEvent;
+class QCloseEvent;
+class QContextMenuEvent;
+class QFocusEvent;
 
 class WXDLLIMPEXP_FWD_CORE wxScrollBar;
 class WXDLLIMPEXP_FWD_CORE wxQtShortcutHandler;
@@ -112,7 +131,7 @@ public:
     virtual bool SetTransparent(wxByte alpha);
     virtual bool CanSetTransparent() { return true; }
 
-    virtual WXWidget GetHandle() const;
+    QWidget *GetHandle() const;
 
     virtual void SetDropTarget( wxDropTarget *dropTarget );
     
@@ -148,7 +167,7 @@ public:
     virtual void QtHandleShortcut ( int command );
 #endif // wxUSE_ACCEL
 
-    virtual QAbstractScrollArea *QtGetScrollBarsContainer() const;
+    virtual QScrollArea *QtGetScrollBarsContainer() const;
 
 protected:
     virtual void DoGetTextExtent(const wxString& string,
@@ -206,7 +225,7 @@ private:
     bool m_mouseInside;
 
 #if wxUSE_ACCEL
-    QList< QShortcut* > m_qtShortcuts;
+    QList< QShortcut* > *m_qtShortcuts;
     wxQtShortcutHandler *m_qtShortcutHandler;
     bool m_processingShortcut;
 #endif // wxUSE_ACCEL
diff --git a/src/qt/accel.cpp b/src/qt/accel.cpp
index 5b9b2f37f0..1ecb0c85fb 100644
--- a/src/qt/accel.cpp
+++ b/src/qt/accel.cpp
@@ -12,6 +12,7 @@
 #include "wx/list.h"
 #include "wx/qt/private/converter.h"
 #include <QtCore/QVariant>
+#include <QtWidgets/QShortcut>
 
 // ----------------------------------------------------------------------------
 // wxAccelList: a list of wxAcceleratorEntries
@@ -81,13 +82,13 @@ wxAcceleratorTable::wxAcceleratorTable(int n, const wxAcceleratorEntry entries[]
     }
 }
 
-QList< QShortcut* > wxAcceleratorTable::ConvertShortcutTable( QWidget *parent ) const
+QList< QShortcut* > *wxAcceleratorTable::ConvertShortcutTable( QWidget *parent ) const
 {   
-    QList< QShortcut* > qtList;
+    QList< QShortcut* > *qtList = new QList< QShortcut* >;
     
     for ( wxAccelList::Node *node = M_ACCELDATA->m_accels.GetFirst(); node; node = node->GetNext() )
     {
-        qtList << ConvertAccelerator( node->GetData(), parent );
+        qtList->push_back(ConvertAccelerator( node->GetData(), parent ));
     }
     
     return qtList;
diff --git a/src/qt/anybutton.cpp b/src/qt/anybutton.cpp
index f09c6ab88f..216b796979 100644
--- a/src/qt/anybutton.cpp
+++ b/src/qt/anybutton.cpp
@@ -14,11 +14,12 @@
     #include "wx/anybutton.h"
 #endif
 
+#include <QtWidgets/QPushButton>
+
 #include "wx/bitmap.h"
 #include "wx/qt/private/utils.h"
 #include "wx/qt/private/winevent.h"
 
-
 class wxQtPushButton : public wxQtEventSignalHandler< QPushButton, wxAnyButton >
 {
 
@@ -64,7 +65,7 @@ void wxAnyButton::SetLabel( const wxString &label )
     m_qtPushButton->setText( wxQtConvertString( label ));
 }
 
-QPushButton *wxAnyButton::GetHandle() const
+QWidget *wxAnyButton::GetHandle() const
 {
     return m_qtPushButton;
 }
diff --git a/src/qt/app.cpp b/src/qt/app.cpp
index c732701684..93f0ccd3d8 100644
--- a/src/qt/app.cpp
+++ b/src/qt/app.cpp
@@ -13,6 +13,7 @@
 #include "wx/qt/private/utils.h"
 #include "wx/qt/private/converter.h"
 #include <QtCore/QStringList>
+#include <QtWidgets/QApplication>
 
 wxIMPLEMENT_DYNAMIC_CLASS(wxApp, wxAppBase);
 
diff --git a/src/qt/apptraits.cpp b/src/qt/apptraits.cpp
index 2f747d7fb9..f196158be2 100644
--- a/src/qt/apptraits.cpp
+++ b/src/qt/apptraits.cpp
@@ -12,7 +12,8 @@
 #include "wx/stdpaths.h"
 #include "wx/evtloop.h"
 
-#include "wx/qt/timer.h"
+#include "wx/timer.h"
+#include "wx/qt/private/timer.h"
 
 #include <QtGlobal>
 
diff --git a/src/qt/bitmap.cpp b/src/qt/bitmap.cpp
index da42ecd9e9..485d9a30c5 100644
--- a/src/qt/bitmap.cpp
+++ b/src/qt/bitmap.cpp
@@ -24,6 +24,7 @@
 #include "wx/bitmap.h"
 #include "wx/cursor.h"
 #include "wx/rawbmp.h"
+#include "wx/qt/colour.h"
 #include "wx/qt/private/converter.h"
 #include "wx/qt/private/utils.h"
 
@@ -213,8 +214,6 @@ wxBitmap::wxBitmap(const wxImage& image, int depth, double WXUNUSED(scale) )
 wxBitmap::wxBitmap(const wxCursor& cursor)
 {
     // note that pixmap could be invalid if is not a pixmap cursor
-    // also, a wxCursor::GetHandle method could be implemented instead of 
-    // accessing the member variable directly  
     QPixmap pix = cursor.GetHandle().pixmap();
     m_refData = new wxBitmapRefData(pix);
 }
diff --git a/src/qt/button.cpp b/src/qt/button.cpp
index 382f12626c..7b7a2e992e 100644
--- a/src/qt/button.cpp
+++ b/src/qt/button.cpp
@@ -21,6 +21,7 @@
 #include "wx/qt/private/utils.h"
 #include "wx/qt/private/winevent.h"
 
+#include <QtWidgets/QPushButton>
 
 wxButton::wxButton()
 {
diff --git a/src/qt/calctrl.cpp b/src/qt/calctrl.cpp
index cf0e216b19..cc051c09dc 100644
--- a/src/qt/calctrl.cpp
+++ b/src/qt/calctrl.cpp
@@ -22,7 +22,7 @@
 #include "wx/qt/private/winevent.h"
 
 #include <QtGui/QTextCharFormat>
-
+#include <QtWidgets/QCalendarWidget>
 
 class wxQtCalendarWidget : public wxQtEventSignalHandler< QCalendarWidget, wxCalendarCtrl >
 {
@@ -316,7 +316,7 @@ void wxCalendarCtrl::SetAttr(size_t day, wxCalendarDateAttr *attr)
     m_qtCalendar->setDateTextFormat(date, format);
 }
 
-QCalendarWidget *wxCalendarCtrl::GetHandle() const
+QWidget *wxCalendarCtrl::GetHandle() const
 {
     return m_qtCalendar;
 }
diff --git a/src/qt/checkbox.cpp b/src/qt/checkbox.cpp
index 5196b684bd..48baecf281 100644
--- a/src/qt/checkbox.cpp
+++ b/src/qt/checkbox.cpp
@@ -13,6 +13,8 @@
 #include "wx/qt/private/converter.h"
 #include "wx/qt/private/winevent.h"
 
+#include <QtWidgets/QCheckBox>
+
 class wxQtCheckBox : public wxQtEventSignalHandler< QCheckBox, wxCheckBox >
 {
 public:
@@ -124,7 +126,7 @@ wxCheckBoxState wxCheckBox::DoGet3StateValue() const
     return wxCHK_UNDETERMINED;
 }
 
-QCheckBox *wxCheckBox::GetHandle() const
+QWidget *wxCheckBox::GetHandle() const
 {
     return m_qtCheckBox;
 }
diff --git a/src/qt/checklst.cpp b/src/qt/checklst.cpp
index df72f98ff7..a1d336c474 100644
--- a/src/qt/checklst.cpp
+++ b/src/qt/checklst.cpp
@@ -10,6 +10,8 @@
 
 #include "wx/checklst.h"
 
+#include <QtWidgets/QListWidgetItem>
+
 wxCheckListBox::wxCheckListBox()
 {
 }
diff --git a/src/qt/choice.cpp b/src/qt/choice.cpp
index 6fad01b70b..19d074284a 100644
--- a/src/qt/choice.cpp
+++ b/src/qt/choice.cpp
@@ -174,7 +174,7 @@ void wxChoice::DoDeleteOneItem(unsigned int pos)
     m_qtComboBox->removeItem(pos);
 }
 
-QComboBox *wxChoice::GetHandle() const
+QWidget *wxChoice::GetHandle() const
 {
     return m_qtComboBox;
 }
diff --git a/src/qt/clipbrd.cpp b/src/qt/clipbrd.cpp
index aa09e516af..582c739d97 100644
--- a/src/qt/clipbrd.cpp
+++ b/src/qt/clipbrd.cpp
@@ -20,6 +20,7 @@
 #include "wx/scopeguard.h"
 #include "wx/qt/private/converter.h"
 
+#include <QtCore/QMimeData>
 
 // ----------------------------------------------------------------------------
 // wxClipboard ctor/dtor
@@ -108,7 +109,7 @@ bool wxClipboard::AddData( wxDataObject *data )
 
         QByteArray bytearray(size, 0);
         data->GetDataHere(format, bytearray.data());
-        MimeData->setData(format.m_MimeType, bytearray);
+        MimeData->setData(wxQtConvertString(format.m_MimeType), bytearray);
     }
 
     delete data;
@@ -143,7 +144,7 @@ bool wxClipboard::GetData( wxDataObject& data )
         const wxDataFormat format(formats[i]);
         
         // is this format supported by clipboard ?
-        if( !MimeData->hasFormat(format.m_MimeType) )
+        if( !MimeData->hasFormat(wxQtConvertString(format.m_MimeType)) )
             continue;
 
         wxTextDataObject *textdata = dynamic_cast<wxTextDataObject*>(&data);
@@ -151,7 +152,7 @@ bool wxClipboard::GetData( wxDataObject& data )
             textdata->SetText(wxQtConvertString(MimeData->text()));
         else
         {
-            QByteArray bytearray = MimeData->data( format.m_MimeType ).data();
+            QByteArray bytearray = MimeData->data( wxQtConvertString(format.m_MimeType) ).data();
             data.SetData(format, bytearray.size(), bytearray.constData());
         }
 
@@ -169,7 +170,7 @@ void wxClipboard::Clear()
 bool wxClipboard::IsSupported( const wxDataFormat& format )
 {
     const QMimeData *data = QtClipboard->mimeData( (QClipboard::Mode)Mode() );
-    return data->hasFormat(format.m_MimeType);
+    return data->hasFormat(wxQtConvertString(format.m_MimeType));
 }
 
 bool wxClipboard::IsSupportedAsync(wxEvtHandler *sink)
diff --git a/src/qt/colordlg.cpp b/src/qt/colordlg.cpp
index 2a09d6fe6b..146c161c40 100644
--- a/src/qt/colordlg.cpp
+++ b/src/qt/colordlg.cpp
@@ -11,6 +11,8 @@
 #include "wx/qt/private/winevent.h"
 #include "wx/colordlg.h"
 
+#include <QtWidgets/QColorDialog>
+
 class wxQtColorDialog : public wxQtEventSignalHandler< QColorDialog, wxDialog >
 {
 public:
@@ -32,7 +34,7 @@ bool wxColourDialog::Create(wxWindow *parent, wxColourData *data )
             QColorDialog::setCustomColor(i, m_data.GetCustomColour(i).GetQColor());
     }
 
-    GetHandle()->setCurrentColor(m_data.GetColour().GetQColor());
+    static_cast<QColorDialog*>(m_qtWindow)->setCurrentColor(m_data.GetColour().GetQColor());
 
     return wxTopLevelWindow::Create( parent, wxID_ANY, "");
 }
@@ -40,10 +42,14 @@ bool wxColourDialog::Create(wxWindow *parent, wxColourData *data )
 wxColourData &wxColourDialog::GetColourData()
 {
     for (int i=0; i<wxColourData::NUM_CUSTOM; i++)
-        m_data.SetCustomColour(i, GetHandle()->customColor(i));
+        m_data.SetCustomColour(i, GetQColorDialog()->customColor(i));
     
-    m_data.SetColour(GetHandle()->currentColor());
+    m_data.SetColour(GetQColorDialog()->currentColor());
     
     return m_data;
 }
 
+QColorDialog *wxColourDialog::GetQColorDialog() const
+{
+    return static_cast<QColorDialog *>(m_qtWindow);
+}
diff --git a/src/qt/combobox.cpp b/src/qt/combobox.cpp
index aee4130860..67757fd2ee 100644
--- a/src/qt/combobox.cpp
+++ b/src/qt/combobox.cpp
@@ -12,7 +12,9 @@
 #include "wx/window.h"
 #include "wx/qt/private/converter.h"
 #include "wx/qt/private/winevent.h"
+
 #include <QtWidgets/QComboBox>
+#include <QtWidgets/QLineEdit>
 
 class wxQtComboBox : public wxQtEventSignalHandler< QComboBox, wxComboBox >
 {
@@ -123,12 +125,12 @@ wxString wxComboBox::DoGetValue() const
 
 void wxComboBox::Popup()
 {
-     GetHandle()->showPopup();
+    static_cast<QComboBox *>(GetHandle())->showPopup();
 }
 
 void wxComboBox::Dismiss()
 {
-    GetHandle()->hidePopup();
+    static_cast<QComboBox *>(GetHandle())->hidePopup();
 }
 
 void wxComboBox::SetSelection( long from, long to )
diff --git a/src/qt/control.cpp b/src/qt/control.cpp
index 5605fd03e0..eacb2409a1 100644
--- a/src/qt/control.cpp
+++ b/src/qt/control.cpp
@@ -11,6 +11,8 @@
 #include "wx/control.h"
 #include "wx/qt/private/converter.h"
 
+#include <QtWidgets/QWidget>
+
 wxIMPLEMENT_DYNAMIC_CLASS(wxControl, wxWindow);
 
 wxControl::wxControl()
diff --git a/src/qt/dataobj.cpp b/src/qt/dataobj.cpp
index 85935786bf..72f7d471d8 100644
--- a/src/qt/dataobj.cpp
+++ b/src/qt/dataobj.cpp
@@ -12,18 +12,17 @@
     #pragma hdrstop
 #endif
 
-#include <QObject>
-
 #include "wx/qt/private/converter.h"
 #include "wx/qt/private/utils.h"
 #include "wx/dataobj.h"
 
+#include <QtCore/QMimeData>
 
 wxDataFormat::wxDataFormat()
 {
 }
 
-static QString DataFormatIdToMimeType( wxDataFormatId formatId )
+static wxString DataFormatIdToMimeType( wxDataFormatId formatId )
 {
     switch(formatId) {
         case wxDF_TEXT: return "text/plain";
@@ -58,32 +57,32 @@ wxDataFormat::wxDataFormat( wxDataFormatId formatId )
 
 wxDataFormat::wxDataFormat(const wxString &id)
 {
-    m_MimeType = wxQtConvertString(id);
+    m_MimeType = id;
 }
 
 wxDataFormat::wxDataFormat(const wxChar *id)
 {
-    m_MimeType = wxQtConvertString((wxString)id);
+    m_MimeType = (wxString)id;
 }
 
 wxDataFormat::wxDataFormat(const QString &id)
 {
-    m_MimeType = id;
+    m_MimeType = wxQtConvertString(id);
 }
 
 void wxDataFormat::SetId( const wxChar *id )
 {
-    m_MimeType = wxQtConvertString((wxString)id);
+    m_MimeType = (wxString)id;
 }
 
 void wxDataFormat::SetId( const wxString& id )
 {
-    m_MimeType = wxQtConvertString(id);
+    m_MimeType = id;
 }
 
 wxString wxDataFormat::GetId() const
 {
-    return wxQtConvertString(m_MimeType);
+    return m_MimeType;
 }
 
 wxDataFormatId wxDataFormat::GetType() const
@@ -119,6 +118,16 @@ bool wxDataFormat::operator!=(const wxDataFormat& format) const
 
 //#############################################################################
 
+wxDataObject::wxDataObject()
+{
+    m_qtMimeData = new QMimeData;
+}
+
+wxDataObject::~wxDataObject()
+{
+    delete m_qtMimeData;
+}
+
 bool wxDataObject::IsSupportedFormat(const wxDataFormat& format, Direction) const
 {
     return wxDataFormat(format) != wxDF_INVALID;
@@ -126,21 +135,21 @@ bool wxDataObject::IsSupportedFormat(const wxDataFormat& format, Direction) cons
 wxDataFormat wxDataObject::GetPreferredFormat(Direction) const
 {
     /* formats are in order of preference */
-    if (m_qtMimeData.formats().count())
-        return m_qtMimeData.formats().first();
+    if (m_qtMimeData->formats().count())
+        return m_qtMimeData->formats().first();
 
     return wxDataFormat();
 }
 
 size_t wxDataObject::GetFormatCount(Direction) const
 {
-    return m_qtMimeData.formats().count();
+    return m_qtMimeData->formats().count();
 }
 
 void wxDataObject::GetAllFormats(wxDataFormat *formats, Direction) const
 {
     int i = 0;
-    foreach (QString format, m_qtMimeData.formats())
+    foreach (QString format, m_qtMimeData->formats())
     {
         formats[i] = format;
         i++;
@@ -149,15 +158,15 @@ void wxDataObject::GetAllFormats(wxDataFormat *formats, Direction) const
 
 size_t wxDataObject::GetDataSize(const wxDataFormat& format) const
 {
-    return  m_qtMimeData.data( format.m_MimeType ).count();
+    return  m_qtMimeData->data( wxQtConvertString(format.m_MimeType) ).count();
 }
 
 bool wxDataObject::GetDataHere(const wxDataFormat& format, void *buf) const
 {
-    if (!m_qtMimeData.hasFormat(format.m_MimeType))
+    if (!m_qtMimeData->hasFormat(wxQtConvertString(format.m_MimeType)))
         return false;
 
-    QByteArray data = m_qtMimeData.data( format.m_MimeType ).data();
+    QByteArray data = m_qtMimeData->data( wxQtConvertString(format.m_MimeType) ).data();
     memcpy(buf, data.constData(), data.size());
     return true;
 }
@@ -165,7 +174,7 @@ bool wxDataObject::GetDataHere(const wxDataFormat& format, void *buf) const
 bool wxDataObject::SetData(const wxDataFormat& format, size_t len, const void * buf)
 {
     QByteArray bytearray((const char*)buf, len);
-    m_qtMimeData.setData(format.m_MimeType, bytearray);
+    m_qtMimeData->setData(wxQtConvertString(format.m_MimeType), bytearray);
 
     return true;
 }
diff --git a/src/qt/dc.cpp b/src/qt/dc.cpp
index 2a17e94726..78e406e0d8 100644
--- a/src/qt/dc.cpp
+++ b/src/qt/dc.cpp
@@ -13,6 +13,8 @@
 #endif
 
 #include <QtGui/QBitmap>
+#include <QtGui/QPen>
+#include <QtGui/QPainter>
 
 #ifndef WX_PRECOMP
     #include "wx/icon.h"
@@ -47,6 +49,8 @@ wxQtDCImpl::wxQtDCImpl( wxDC *owner )
     m_clippingRegion = new wxRegion;
     m_qtImage = NULL;
     m_rasterColourOp = wxQtNONE;
+    m_qtPenColor = new QColor;
+    m_qtBrushColor = new QColor;
     m_ok = true;
 }
 
@@ -60,8 +64,10 @@ wxQtDCImpl::~wxQtDCImpl()
         }
         delete m_qtPainter;
     }
-    if ( m_clippingRegion != NULL )
-        delete m_clippingRegion;
+
+    delete m_clippingRegion;
+    delete m_qtPenColor;
+    delete m_qtBrushColor;
 }
 
 void wxQtDCImpl::QtPreparePainter( )
@@ -197,6 +203,10 @@ void wxQtDCImpl::SetBackgroundMode(int mode)
     m_backgroundMode = mode;
 }
 
+#include <QtGui/QPen>
+#include <QtGui/QPainter>
+#include <QtGui/QScreen>
+#include <QtWidgets/QApplication>
 
 #if wxUSE_PALETTE
 void wxQtDCImpl::SetPalette(const wxPalette& WXUNUSED(palette))
@@ -284,8 +294,8 @@ void wxQtDCImpl::SetLogicalFunction(wxRasterOperationMode function)
         m_rasterColourOp = rasterColourOp;
 
         // Restore original colours and apply new mode
-        SetPenColour( m_qtPainter, m_qtPenColor );
-        SetBrushColour( m_qtPainter, m_qtPenColor );
+        SetPenColour( m_qtPainter, *m_qtPenColor );
+        SetBrushColour( m_qtPainter, *m_qtPenColor );
 
         ApplyRasterColourOp();
     }
@@ -294,8 +304,8 @@ void wxQtDCImpl::SetLogicalFunction(wxRasterOperationMode function)
 void wxQtDCImpl::ApplyRasterColourOp()
 {
     // Save colours
-    m_qtPenColor = m_qtPainter->pen().color();
-    m_qtBrushColor = m_qtPainter->brush().color();
+    *m_qtPenColor = m_qtPainter->pen().color();
+    *m_qtBrushColor = m_qtPainter->brush().color();
 
     // Apply op
     switch ( m_rasterColourOp )
@@ -309,8 +319,8 @@ void wxQtDCImpl::ApplyRasterColourOp()
             SetBrushColour( m_qtPainter, QColor( Qt::black ) );
             break;
         case wxQtINVERT:
-            SetPenColour( m_qtPainter, QColor( ~m_qtPenColor.rgb() ) );
-            SetBrushColour( m_qtPainter, QColor( ~m_qtBrushColor.rgb() ) );
+            SetPenColour( m_qtPainter, QColor( ~m_qtPenColor->rgb() ) );
+            SetBrushColour( m_qtPainter, QColor( ~m_qtBrushColor->rgb() ) );
             break;
         case wxQtNONE:
             // No op
diff --git a/src/qt/dcclient.cpp b/src/qt/dcclient.cpp
index 0a69244bfd..eea8088a42 100644
--- a/src/qt/dcclient.cpp
+++ b/src/qt/dcclient.cpp
@@ -22,6 +22,8 @@
 #include "wx/dcclient.h"
 #include "wx/qt/dcclient.h"
 
+#include <QtWidgets/QScrollArea>
+#include <QtGui/QPainter>
 
 //##############################################################################
 
diff --git a/src/qt/dcmemory.cpp b/src/qt/dcmemory.cpp
index 3609241a0e..2898270d7f 100644
--- a/src/qt/dcmemory.cpp
+++ b/src/qt/dcmemory.cpp
@@ -11,6 +11,8 @@
 #include "wx/dcmemory.h"
 #include "wx/qt/dcmemory.h"
 
+#include <QtGui/QPainter>
+
 wxMemoryDCImpl::wxMemoryDCImpl( wxMemoryDC *owner )
     : wxQtDCImpl( owner )
 {
diff --git a/src/qt/dialog.cpp b/src/qt/dialog.cpp
index 3d655cba4b..892f52cc44 100644
--- a/src/qt/dialog.cpp
+++ b/src/qt/dialog.cpp
@@ -12,6 +12,7 @@
 #include "wx/qt/private/utils.h"
 #include "wx/qt/private/winevent.h"
 
+#include <QtWidgets/QDialog>
 
 class wxQtDialog : public wxQtEventSignalHandler< QDialog, wxDialog >
 {
@@ -58,7 +59,9 @@ bool wxDialog::Create( wxWindow *parent, wxWindowID id,
     style |= wxTAB_TRAVERSAL;
 
     m_qtWindow = new wxQtDialog( parent, this );
+    
     PostCreation();
+
     return wxTopLevelWindow::Create( parent, id, title, pos, size, style, name );
 }
 
@@ -66,24 +69,25 @@ int wxDialog::ShowModal()
 {
     wxCHECK_MSG( GetHandle() != NULL, -1, "Invalid dialog" );
     
-    return GetHandle()->exec() ? wxID_OK : wxID_CANCEL;
+    return GetDialogHandle()->exec() ? wxID_OK : wxID_CANCEL;
 }
 
 void wxDialog::EndModal(int retCode)
 {
-    wxCHECK_RET( GetHandle() != NULL, "Invalid dialog" );
-    
-    GetHandle()->done( retCode );
+    wxCHECK_RET( GetDialogHandle() != NULL, "Invalid dialog" );
+
+    SetReturnCode(retCode);
+    GetDialogHandle()->done( retCode );
 }
 
 bool wxDialog::IsModal() const
 {
-    wxCHECK_MSG( GetHandle() != NULL, false, "Invalid dialog" );
+    wxCHECK_MSG( GetDialogHandle() != NULL, false, "Invalid dialog" );
 
-    return GetHandle()->isModal();
+    return GetDialogHandle()->isModal();
 }
 
-QDialog *wxDialog::GetHandle() const
+QDialog *wxDialog::GetDialogHandle() const
 {
     return static_cast<QDialog*>(m_qtWindow);
 }
diff --git a/src/qt/evtloop.cpp b/src/qt/evtloop.cpp
index 853dd6e7b3..97ca3a98ba 100644
--- a/src/qt/evtloop.cpp
+++ b/src/qt/evtloop.cpp
@@ -16,6 +16,23 @@
 #include <QtCore/QCoreApplication>
 #include <QtCore/QAbstractEventDispatcher>
 #include <QtCore/QSocketNotifier>
+#include <QtCore/QTimer>
+
+#include <QtWidgets/QApplication>
+
+class wxQtIdleTimer : public QTimer
+{
+
+public:
+    wxQtIdleTimer( wxQtEventLoopBase *eventLoop );
+    virtual bool eventFilter( QObject * watched, QEvent * event  );
+
+private:
+    void idle();
+
+private:
+    wxQtEventLoopBase *m_eventLoop;
+};
 
 wxQtIdleTimer::wxQtIdleTimer( wxQtEventLoopBase *eventLoop )
 {
diff --git a/src/qt/filedlg.cpp b/src/qt/filedlg.cpp
index d721e66e36..4fb0920ff8 100644
--- a/src/qt/filedlg.cpp
+++ b/src/qt/filedlg.cpp
@@ -113,7 +113,7 @@ wxString wxFileDialog::GetPath() const
 
 void wxFileDialog::GetPaths(wxArrayString& paths) const
 {
-    QStringList selectedfiles = GetHandle()->selectedFiles();
+    QStringList selectedfiles = GetQFileDialog()->selectedFiles();
     foreach (QString file, selectedfiles)
         paths.Add(wxQtConvertString(file));
 }
@@ -130,7 +130,7 @@ wxString wxFileDialog::GetFilename() const
 
 void wxFileDialog::GetFilenames(wxArrayString& files) const
 {
-    QStringList selectedfiles = GetHandle()->selectedFiles();
+    QStringList selectedfiles = GetQFileDialog()->selectedFiles();
     foreach (QString file, selectedfiles )
     {
         wxFileName fn = wxQtConvertString(file);
@@ -141,9 +141,9 @@ void wxFileDialog::GetFilenames(wxArrayString& files) const
 int wxFileDialog::GetFilterIndex() const
 {
     int index = 0;
-    foreach (QString filter, GetHandle()->nameFilters())
+    foreach (QString filter, GetQFileDialog()->nameFilters())
     {
-        if (filter == GetHandle()->selectedNameFilter())
+        if (filter == GetQFileDialog()->selectedNameFilter())
             return index;
         index++;
     }
@@ -153,17 +153,17 @@ int wxFileDialog::GetFilterIndex() const
 
 void wxFileDialog::SetMessage(const wxString& message)
 {
-    GetHandle()->setLabelText(QFileDialog::LookIn, wxQtConvertString(message));
+    GetQFileDialog()->setLabelText(QFileDialog::LookIn, wxQtConvertString(message));
 }
 
 void wxFileDialog::SetPath(const wxString& path)
 {
-    GetHandle()->selectFile(wxQtConvertString(path));
+    GetQFileDialog()->selectFile(wxQtConvertString(path));
 }
 
 void wxFileDialog::SetDirectory(const wxString& dir)
 {
-    GetHandle()->setDirectory(wxQtConvertString(dir));
+    GetQFileDialog()->setDirectory(wxQtConvertString(dir));
 }
 
 void wxFileDialog::SetFilename(const wxString& name)
@@ -173,19 +173,19 @@ void wxFileDialog::SetFilename(const wxString& name)
 
 void wxFileDialog::SetWildcard(const wxString& wildCard)
 {
-    GetHandle()->setNameFilter(wxQtConvertString(wildCard));
+    GetQFileDialog()->setNameFilter(wxQtConvertString(wildCard));
 }
 
 void wxFileDialog::SetFilterIndex(int filterIndex)
 {
-    QStringList filters = GetHandle()->nameFilters();
+    QStringList filters = GetQFileDialog()->nameFilters();
     if (filterIndex < 0 || filterIndex >= filters.size())
         return;
 
-    GetHandle()->setNameFilter(filters.at(filterIndex));
+    GetQFileDialog()->setNameFilter(filters.at(filterIndex));
 }
 
-QFileDialog *wxFileDialog::GetHandle() const
+QFileDialog *wxFileDialog::GetQFileDialog() const
 {
     return static_cast<QFileDialog *>(m_qtWindow);
 }
@@ -237,7 +237,7 @@ bool wxDirDialog::Create(wxWindow *parent,
 
 wxString wxDirDialog::GetPath() const
 {
-    QStringList selectedfiles = GetHandle()->selectedFiles();
+    QStringList selectedfiles = GetQFileDialog()->selectedFiles();
     if (selectedfiles.size() > 0)
         return wxQtConvertString(selectedfiles.first());
 
@@ -246,10 +246,10 @@ wxString wxDirDialog::GetPath() const
 
 void wxDirDialog::SetPath(const wxString& path)
 {
-    GetHandle()->selectFile(wxQtConvertString(path));
+    GetQFileDialog()->selectFile(wxQtConvertString(path));
 }
 
-QFileDialog *wxDirDialog::GetHandle() const
+QFileDialog *wxDirDialog::GetQFileDialog() const
 {
     return static_cast<QFileDialog *>(m_qtWindow);
 }
diff --git a/src/qt/fontdlg.cpp b/src/qt/fontdlg.cpp
index 679cbebde5..361dcf08af 100644
--- a/src/qt/fontdlg.cpp
+++ b/src/qt/fontdlg.cpp
@@ -11,6 +11,8 @@
 #include "wx/qt/private/winevent.h"
 #include "wx/fontdlg.h"
 
+#include <QtWidgets/QFontDialog>
+
 class wxQtFontDialog : public wxQtEventSignalHandler< QFontDialog, wxFontDialog >
 {
 public:
@@ -31,7 +33,7 @@ wxIMPLEMENT_DYNAMIC_CLASS(wxFontDialog, wxDialog);
 bool wxFontDialog::DoCreate(wxWindow *parent)
 {
     m_qtWindow = new wxQtFontDialog( parent, this );
-    GetHandle()->setCurrentFont(m_fontData.GetInitialFont().GetHandle());
+    static_cast<QFontDialog*>(m_qtWindow)->setCurrentFont(m_fontData.GetInitialFont().GetHandle());
     return wxFontDialogBase::DoCreate(parent);
 }
 
diff --git a/src/qt/frame.cpp b/src/qt/frame.cpp
index 7b54944924..3f33119c4a 100644
--- a/src/qt/frame.cpp
+++ b/src/qt/frame.cpp
@@ -12,8 +12,6 @@
     #pragma hdrstop
 #endif
 
-#include <QtWidgets/QScrollArea>
-
 #ifndef WX_PRECOMP
     #include "wx/menu.h"
     #include "wx/toolbar.h"
@@ -24,6 +22,9 @@
 #include "wx/qt/private/converter.h"
 #include "wx/qt/private/winevent.h"
 
+#include <QtWidgets/QScrollArea>
+#include <QtWidgets/QMainWindow>
+#include <QtWidgets/QMenuBar>
 
 class wxQtMainWindow : public wxQtEventSignalHandler< QMainWindow, wxFrame >
 {
@@ -56,7 +57,7 @@ wxFrame::wxFrame( wxWindow *parent, wxWindowID id, const wxString& title,
 wxFrame::~wxFrame()
 {
     // central widget should be deleted by qt when the main window is destroyed
-    QtStoreWindowPointer( GetHandle()->centralWidget(), NULL );
+    QtStoreWindowPointer( GetQMainWindow()->centralWidget(), NULL );
 }
 
 bool wxFrame::Create( wxWindow *parent, wxWindowID id, const wxString& title,
@@ -67,7 +68,7 @@ bool wxFrame::Create( wxWindow *parent, wxWindowID id, const wxString& title,
     // TODO: Could we use a wxPanel as the central widget? If so then we could
     // remove wxWindow::QtReparent.
 
-    GetHandle()->setCentralWidget( new wxQtCentralWidget( parent, this ) );
+    GetQMainWindow()->setCentralWidget( new wxQtCentralWidget( parent, this ) );
 
     PostCreation();
 
@@ -83,13 +84,13 @@ void wxFrame::SetMenuBar( wxMenuBar *menuBar )
         wxCHECK_RET( menuBar->GetHandle(),
                      "Using a replaced menu bar is not supported in wxQT");
         // Warning: Qt main window takes ownership of the QMenuBar pointer:
-        GetHandle()->setMenuBar( menuBar->GetHandle() );
+        GetQMainWindow()->setMenuBar( menuBar->GetQMenuBar() );
     }
     else
     {
         // Creating an empty menu bar should hide it and free the previous:
         QMenuBar *qmenubar = new QMenuBar(GetHandle());
-        GetHandle()->setMenuBar( qmenubar );
+        GetQMainWindow()->setMenuBar( qmenubar );
     }
     wxFrameBase::SetMenuBar( menuBar );
 }
@@ -100,14 +101,14 @@ void wxFrame::SetStatusBar( wxStatusBar *statusBar )
     // TODO: add a mechanism like Detach in menus to avoid issues
     if ( statusBar != NULL )
     {
-        GetHandle()->setStatusBar( statusBar->GetHandle() );
+        GetQMainWindow()->setStatusBar( statusBar->GetQStatusBar() );
         // Update statusbar sizes now that it has a size
         statusBar->Refresh();
     }
     else
     {
         // Remove the current status bar
-        GetHandle()->setStatusBar(NULL);
+        GetQMainWindow()->setStatusBar(NULL);
     }
     wxFrameBase::SetStatusBar( statusBar );
 }
@@ -122,11 +123,11 @@ void wxFrame::SetToolBar(wxToolBar *toolbar)
         if (toolbar->HasFlag(wxTB_TOP))    area |= Qt::TopToolBarArea;
         if (toolbar->HasFlag(wxTB_BOTTOM)) area |= Qt::BottomToolBarArea;
 
-        GetHandle()->addToolBar((Qt::ToolBarArea)area, toolbar->GetHandle());
+        GetQMainWindow()->addToolBar((Qt::ToolBarArea)area, toolbar->GetQToolBar());
     }
     else if ( m_frameToolBar != NULL )
     {
-        GetHandle()->removeToolBar(m_frameToolBar->GetHandle());
+        GetQMainWindow()->removeToolBar(m_frameToolBar->GetQToolBar());
     }
     wxFrameBase::SetToolBar( toolbar );
 }
@@ -135,7 +136,7 @@ void wxFrame::SetWindowStyleFlag( long style )
 {
     wxWindow::SetWindowStyleFlag( style );
 
-    Qt::WindowFlags qtFlags = GetHandle()->windowFlags();
+    Qt::WindowFlags qtFlags = GetQMainWindow()->windowFlags();
 
     if ( HasFlag( wxFRAME_TOOL_WINDOW ) )
     {
@@ -143,14 +144,14 @@ void wxFrame::SetWindowStyleFlag( long style )
         qtFlags |= Qt::Tool;
     }
 
-    GetHandle()->setWindowFlags( qtFlags );
+    GetQMainWindow()->setWindowFlags( qtFlags );
 }
 
 void wxFrame::AddChild( wxWindowBase *child )
 {
     // Make sure all children are children of the central widget:
 
-    QtReparent( child->GetHandle(), GetHandle()->centralWidget() );
+    QtReparent( child->GetHandle(), GetQMainWindow()->centralWidget() );
 
     wxFrameBase::AddChild( child );
 }
@@ -160,9 +161,9 @@ void wxFrame::RemoveChild( wxWindowBase *child )
     wxFrameBase::RemoveChild( child );
 }
 
-QAbstractScrollArea *wxFrame::QtGetScrollBarsContainer() const
+QScrollArea *wxFrame::QtGetScrollBarsContainer() const
 {
-    return dynamic_cast <QAbstractScrollArea *> (GetHandle()->centralWidget() );
+    return dynamic_cast <QScrollArea *> (GetQMainWindow()->centralWidget() );
 }
 
 void wxFrame::DoGetClientSize(int *width, int *height) const
@@ -179,6 +180,11 @@ void wxFrame::DoGetClientSize(int *width, int *height) const
     }
 }
 
+QMainWindow *wxFrame::GetQMainWindow() const
+{
+    return static_cast<QMainWindow*>(m_qtWindow);
+}
+
 //=============================================================================
 
 wxQtMainWindow::wxQtMainWindow( wxWindow *parent, wxFrame *handler )
diff --git a/src/qt/gauge.cpp b/src/qt/gauge.cpp
index da3bbc9687..ffa1c0963d 100644
--- a/src/qt/gauge.cpp
+++ b/src/qt/gauge.cpp
@@ -12,6 +12,7 @@
 #include "wx/qt/private/converter.h"
 #include "wx/qt/private/winevent.h"
 
+#include <QtWidgets/QProgressBar>
 
 class wxQtProgressBar : public wxQtEventSignalHandler< QProgressBar, wxGauge >
 {
@@ -62,7 +63,7 @@ bool wxGauge::Create(wxWindow *parent,
 }
 
 
-QProgressBar *wxGauge::GetHandle() const
+QWidget *wxGauge::GetHandle() const
 {
     return m_qtProgressBar;
 }
diff --git a/src/qt/glcanvas.cpp b/src/qt/glcanvas.cpp
index 13acf97448..0106d8620b 100644
--- a/src/qt/glcanvas.cpp
+++ b/src/qt/glcanvas.cpp
@@ -12,6 +12,8 @@
 #include "wx/qt/private/winevent.h"
 #include "wx/glcanvas.h"
 
+#include <QtOpenGL/QGLWidget>
+
 class wxQtGLWidget : public wxQtEventSignalHandler< QGLWidget, wxGLCanvas >
 {
 public:
@@ -378,7 +380,7 @@ bool wxGLCanvas::Create(wxWindow *parent,
 
 bool wxGLCanvas::SwapBuffers()
 {
-    GetHandle()->swapBuffers();
+    static_cast<QGLWidget *>(m_qtWindow)->swapBuffers();
     return true;
 }
 
diff --git a/src/qt/listbox.cpp b/src/qt/listbox.cpp
index 1d63f39a9c..d465e4ce0e 100644
--- a/src/qt/listbox.cpp
+++ b/src/qt/listbox.cpp
@@ -11,6 +11,7 @@
 #include "wx/listbox.h"
 #include "wx/qt/private/winevent.h"
 
+#include <QtWidgets/QListWidget>
 
 class wxQtListWidget : public wxQtEventSignalHandler< QListWidget, wxListBox >
 {
@@ -225,7 +226,7 @@ void wxListBox::DoDeleteOneItem(unsigned int pos)
     delete item;
 }
 
-QListWidget *wxListBox::GetHandle() const
+QWidget *wxListBox::GetHandle() const
 {
     return m_qtListWidget;
 }
diff --git a/src/qt/listctrl.cpp b/src/qt/listctrl.cpp
index ad8ecf2b8b..9444cfdde7 100644
--- a/src/qt/listctrl.cpp
+++ b/src/qt/listctrl.cpp
@@ -22,6 +22,7 @@
 #include "wx/imaglist.h"
 #include "wx/qt/private/winevent.h"
 
+#include <QtWidgets/QTreeWidget>
 
 class wxQtTreeWidget : public wxQtEventSignalHandler< QTreeWidget, wxListCtrl >
 {
@@ -916,7 +917,7 @@ int wxListCtrl::OnGetItemColumnImage(long item, long column) const
     return -1;
 }
 
-QTreeWidget *wxListCtrl::GetHandle() const
+QWidget *wxListCtrl::GetHandle() const
 {
     return m_qtTreeWidget;
 }
diff --git a/src/qt/mdi.cpp b/src/qt/mdi.cpp
index edfaea9d5f..3655a355de 100644
--- a/src/qt/mdi.cpp
+++ b/src/qt/mdi.cpp
@@ -14,7 +14,9 @@
 #include "wx/qt/private/utils.h"
 #include "wx/qt/private/converter.h"
 #include "wx/qt/private/winevent.h"
+
 #include <QtWidgets/QMdiArea>
+#include <QtWidgets/QMainWindow>
 
 // Main MDI window helper
 
@@ -69,7 +71,7 @@ bool wxMDIParentFrame::Create(wxWindow *parent,
     if ( !m_clientWindow->CreateClient(this, GetWindowStyleFlag()) )
         return false;
 
-    GetHandle()->setCentralWidget( client->GetHandle() );
+    GetQMainWindow()->setCentralWidget( client->GetHandle() );
 
     PostCreation();
 
@@ -116,7 +118,7 @@ bool wxMDIChildFrame::Create(wxMDIParentFrame *parent,
     if (ok)
     {
         // Add the window to the internal MDI client area:
-        static_cast<QMdiArea*>(parent->GetHandle()->centralWidget())->addSubWindow(GetHandle());
+        static_cast<QMdiArea*>(parent->GetQMainWindow()->centralWidget())->addSubWindow(GetHandle());
     }
     return ok;
 }
diff --git a/src/qt/menu.cpp b/src/qt/menu.cpp
index f07668b9c6..a0433d7229 100644
--- a/src/qt/menu.cpp
+++ b/src/qt/menu.cpp
@@ -12,6 +12,8 @@
 #include "wx/qt/private/utils.h"
 #include "wx/qt/private/converter.h"
 
+#include <QtWidgets/QMenu>
+#include <QtWidgets/QMenuBar>
 
 static void ApplyStyle( QMenu *qtMenu, long style )
 {
@@ -245,7 +247,7 @@ void wxMenuBar::Detach()
     wxMenuBarBase::Detach();
 }
 
-QMenuBar *wxMenuBar::GetHandle() const
+QWidget *wxMenuBar::GetHandle() const
 {
     return m_qtMenuBar;
 }
diff --git a/src/qt/menuitem.cpp b/src/qt/menuitem.cpp
index 5d7bac2ec2..eab049e342 100644
--- a/src/qt/menuitem.cpp
+++ b/src/qt/menuitem.cpp
@@ -15,6 +15,8 @@
 #include "wx/qt/private/converter.h"
 #include "wx/qt/private/winevent.h"
 
+#include <QtWidgets/QAction>
+#include <QtWidgets/QMenuBar>
 
 class wxQtAction : public QAction, public wxQtSignalHandler< wxMenuItem >
 {
diff --git a/src/qt/msgdlg.cpp b/src/qt/msgdlg.cpp
index 7b57eb9e5b..b80c004564 100644
--- a/src/qt/msgdlg.cpp
+++ b/src/qt/msgdlg.cpp
@@ -27,39 +27,40 @@ wxMessageDialog::wxMessageDialog( wxWindow *parent, const wxString& message,
         const wxString& caption, long style, const wxPoint& pos )
     : wxMessageDialogBase( parent, message, caption, style )
 {
-    m_qtWindow = new wxQtMessageDialog( parent, this );
+    wxQtMessageDialog *dlg = new wxQtMessageDialog( parent, this );
+    m_qtWindow = dlg;
 
     // Set properties
     Move( pos );
-    GetHandle()->setText( wxQtConvertString( message ) );
-    GetHandle()->setWindowTitle( wxQtConvertString( caption ) );
+    dlg->setText( wxQtConvertString( message ) );
+    dlg->setWindowTitle( wxQtConvertString( caption ) );
     
     // Apply the style
     SetWindowStyleFlag( style );
 
     // Buttons
     if ( style & wxOK )
-        GetHandle()->addButton( QMessageBox::Ok );
+        dlg->addButton( QMessageBox::Ok );
     if ( style & wxCANCEL )
-        GetHandle()->addButton( QMessageBox::Cancel );
+        dlg->addButton( QMessageBox::Cancel );
     if ( style & wxYES_NO )
     {
-        GetHandle()->addButton( QMessageBox::Yes );
-        GetHandle()->addButton( QMessageBox::No );
+        dlg->addButton( QMessageBox::Yes );
+        dlg->addButton( QMessageBox::No );
     }
 
     // Default button
     if ( style & wxNO_DEFAULT )
-        GetHandle()->setDefaultButton( QMessageBox::No );
+        dlg->setDefaultButton( QMessageBox::No );
     else if ( style & wxCANCEL_DEFAULT )
-        GetHandle()->setDefaultButton( QMessageBox::Cancel );
+        dlg->setDefaultButton( QMessageBox::Cancel );
     else
     {
         // Default to OK or Yes
         if ( style & wxOK )
-            GetHandle()->setDefaultButton( QMessageBox::Ok );
+            dlg->setDefaultButton( QMessageBox::Ok );
         else
-            GetHandle()->setDefaultButton( QMessageBox::Yes );
+            dlg->setDefaultButton( QMessageBox::Yes );
     }
 
     // Icon
@@ -67,31 +68,31 @@ wxMessageDialog::wxMessageDialog( wxWindow *parent, const wxString& message,
     if ( style & wxICON_NONE )
     {
         numIcons++;
-        GetHandle()->setIcon( QMessageBox::NoIcon );
+        dlg->setIcon( QMessageBox::NoIcon );
     }
 
     if ( style & wxICON_EXCLAMATION )
     {
         numIcons++;
-        GetHandle()->setIcon( QMessageBox::Warning );
+        dlg->setIcon( QMessageBox::Warning );
     }
 
     if ( style & wxICON_ERROR || style & wxICON_HAND )
     {
         numIcons++;
-        GetHandle()->setIcon( QMessageBox::Critical );
+        dlg->setIcon( QMessageBox::Critical );
     }
 
     if ( style & wxICON_QUESTION )
     {
         numIcons++;
-        GetHandle()->setIcon( QMessageBox::Question );
+        dlg->setIcon( QMessageBox::Question );
     }
         
     if ( style & wxICON_INFORMATION )
     {
         numIcons++;
-        GetHandle()->setIcon( QMessageBox::Information );
+        dlg->setIcon( QMessageBox::Information );
     }
 
     wxCHECK_RET( numIcons <= 1, "Multiple icon definitions" );
@@ -99,23 +100,23 @@ wxMessageDialog::wxMessageDialog( wxWindow *parent, const wxString& message,
     {
         // Use default
         if ( style & wxYES_NO )
-            GetHandle()->setIcon( QMessageBox::Question );
+            dlg->setIcon( QMessageBox::Question );
         else
-            GetHandle()->setIcon( QMessageBox::Information );
+            dlg->setIcon( QMessageBox::Information );
     }
 
     if ( style & wxSTAY_ON_TOP )
-        GetHandle()->setWindowModality( Qt::ApplicationModal );
+        dlg->setWindowModality( Qt::ApplicationModal );
 
     PostCreation();
 }
 
 int wxMessageDialog::ShowModal()
 {
-    wxCHECK_MSG( GetHandle(), -1, "Invalid dialog" );
+    wxCHECK_MSG( m_qtWindow, -1, "Invalid dialog" );
     
     // Exec may return a wx identifier if a close event is generated
-    int ret = GetHandle()->exec();
+    int ret = static_cast<QDialog*>(m_qtWindow)->exec();
     switch ( ret )
     {
         case QMessageBox::Ok:
@@ -132,11 +133,6 @@ int wxMessageDialog::ShowModal()
     }                                        
 }
 
-QMessageBox *wxMessageDialog::GetHandle() const
-{
-    return static_cast<QMessageBox*>(m_qtWindow);
-}
-
 wxMessageDialog::~wxMessageDialog()
 {
 }
diff --git a/src/qt/notebook.cpp b/src/qt/notebook.cpp
index 2a971f5b95..5a3b8affcf 100644
--- a/src/qt/notebook.cpp
+++ b/src/qt/notebook.cpp
@@ -13,6 +13,8 @@
 #include "wx/qt/private/converter.h"
 #include "wx/qt/private/winevent.h"
 
+#include <QtWidgets/QTabWidget>
+
 class wxQtTabWidget : public wxQtEventSignalHandler< QTabWidget, wxNotebook >
 {
 public:
@@ -199,7 +201,7 @@ wxWindow *wxNotebook::DoRemovePage(size_t page)
     return QtRetrieveWindowPointer( qtWidget );
 }
 
-QTabWidget *wxNotebook::GetHandle() const
+QWidget *wxNotebook::GetHandle() const
 {
     return m_qtTabWidget;
 }
diff --git a/src/qt/radiobox.cpp b/src/qt/radiobox.cpp
index f5c01515bc..da8c90baa6 100644
--- a/src/qt/radiobox.cpp
+++ b/src/qt/radiobox.cpp
@@ -15,7 +15,8 @@
 #include <QtWidgets/QCheckBox>
 #include <QtWidgets/QGroupBox>
 #include <QtWidgets/QRadioButton>
-
+#include <QtWidgets/QButtonGroup>
+#include <QtWidgets/QBoxLayout>
 
 class wxQtRadioBox : public wxQtEventSignalHandler< QGroupBox, wxRadioBox >
 {
@@ -236,7 +237,7 @@ int wxRadioBox::GetSelection() const
         return wxNOT_FOUND;
 }
 
-QGroupBox *wxRadioBox::GetHandle() const
+QWidget *wxRadioBox::GetHandle() const
 {
     return m_qtGroupBox;
 }
diff --git a/src/qt/radiobut.cpp b/src/qt/radiobut.cpp
index 00fafd8a18..64e2100cd4 100644
--- a/src/qt/radiobut.cpp
+++ b/src/qt/radiobut.cpp
@@ -11,6 +11,8 @@
 #include "wx/radiobut.h"
 #include "wx/qt/private/converter.h"
 
+#include <QtWidgets/QRadioButton>
+
 wxRadioButton::wxRadioButton()
 {
 }
@@ -52,7 +54,7 @@ bool wxRadioButton::GetValue() const
     return m_qtRadioButton->isChecked();
 }
 
-QRadioButton *wxRadioButton::GetHandle() const
+QWidget *wxRadioButton::GetHandle() const
 {
     return m_qtRadioButton;
 }
diff --git a/src/qt/region.cpp b/src/qt/region.cpp
index b2b0ff4ed1..6cf474023a 100644
--- a/src/qt/region.cpp
+++ b/src/qt/region.cpp
@@ -215,9 +215,9 @@ bool wxRegion::DoXor(const wxRegion& region)
     return true;
 }
 
-QRegion wxRegion::GetHandle() const
+const QRegion &wxRegion::GetHandle() const
 {
-    wxCHECK_MSG( IsOk(), QRegion(), "Invalid region" );
+    wxCHECK_MSG( IsOk(), GetHandle(), "Invalid region" );
 
     return M_REGIONDATA;
 }
diff --git a/src/qt/scrolbar.cpp b/src/qt/scrolbar.cpp
index bd445debf8..99db6cc451 100644
--- a/src/qt/scrolbar.cpp
+++ b/src/qt/scrolbar.cpp
@@ -12,6 +12,7 @@
 #include "wx/qt/private/utils.h"
 #include "wx/qt/private/winevent.h"
 
+#include <QtWidgets/QScrollBar>
 
 class wxQtScrollBar : public wxQtEventSignalHandler< QScrollBar, wxScrollBar >
 {
@@ -109,7 +110,7 @@ void wxScrollBar::SetScrollbar(int position, int WXUNUSED(thumbSize),
     }
 }
 
-QScrollBar *wxScrollBar::GetHandle() const
+QWidget *wxScrollBar::GetHandle() const
 {
     return m_qtScrollBar;
 }
diff --git a/src/qt/slider.cpp b/src/qt/slider.cpp
index f3d95b5115..9efc54d529 100644
--- a/src/qt/slider.cpp
+++ b/src/qt/slider.cpp
@@ -12,6 +12,7 @@
 #include "wx/qt/private/converter.h"
 #include "wx/qt/private/winevent.h"
 
+#include <QtWidgets/QSlider>
 
 class wxQtSlider : public wxQtEventSignalHandler< QSlider, wxSlider >
 {
@@ -163,7 +164,7 @@ int wxSlider::GetThumbLength() const
 }
 
 
-QSlider *wxSlider::GetHandle() const
+QWidget *wxSlider::GetHandle() const
 {
     return m_qtSlider;
 }
diff --git a/src/qt/spinbutt.cpp b/src/qt/spinbutt.cpp
index 3488a476f8..0fca8ba9e4 100644
--- a/src/qt/spinbutt.cpp
+++ b/src/qt/spinbutt.cpp
@@ -11,6 +11,7 @@
 #include "wx/spinbutt.h"
 #include "wx/qt/private/winevent.h"
 
+#include <QtWidgets/QSpinBox>
 
 class wxQtSpinButton : public wxQtEventSignalHandler< QSpinBox, wxSpinButton  >
 {
@@ -81,7 +82,7 @@ void wxSpinButton::SetValue(int val)
     m_qtSpinBox->setValue( val );
 }
 
-QSpinBox *wxSpinButton::GetHandle() const
+QWidget *wxSpinButton::GetHandle() const
 {
     return m_qtSpinBox;
 }
diff --git a/src/qt/spinctrl.cpp b/src/qt/spinctrl.cpp
index de7dfd94d3..9cb720d228 100644
--- a/src/qt/spinctrl.cpp
+++ b/src/qt/spinctrl.cpp
@@ -15,6 +15,8 @@
 #include "wx/qt/private/converter.h"
 #include "wx/qt/private/winevent.h"
 
+#include <QtWidgets/QSpinBox>
+
 template< typename T, typename Widget >
 wxSpinCtrlQt< T, Widget >::wxSpinCtrlQt()
 {
@@ -117,7 +119,7 @@ void wxSpinCtrlQt< T, Widget >::SetSelection(long WXUNUSED(WXUNUSED(from)), long
 }
 
 template< typename T, typename Widget >
-Widget *wxSpinCtrlQt< T, Widget >::GetHandle() const
+QWidget *wxSpinCtrlQt< T, Widget >::GetHandle() const
 {
     return m_qtSpinBox;
 }
diff --git a/src/qt/statbmp.cpp b/src/qt/statbmp.cpp
index faa1540d33..b4dbde30f0 100644
--- a/src/qt/statbmp.cpp
+++ b/src/qt/statbmp.cpp
@@ -11,6 +11,8 @@
 #include "wx/statbmp.h"
 #include "wx/qt/private/winevent.h"
 
+#include <QtWidgets/QLabel>
+
 class wxQtStaticBmp : public wxQtEventSignalHandler< QLabel, wxStaticBitmap >
 {
 public:
@@ -80,7 +82,7 @@ wxIcon wxStaticBitmap::GetIcon() const
     return icon;
 }
 
-QLabel *wxStaticBitmap::GetHandle() const
+QWidget *wxStaticBitmap::GetHandle() const
 {
     return m_qtLabel;
 }
diff --git a/src/qt/statbox.cpp b/src/qt/statbox.cpp
index be9825e0bb..6af3e2ddb6 100644
--- a/src/qt/statbox.cpp
+++ b/src/qt/statbox.cpp
@@ -50,7 +50,7 @@ bool wxStaticBox::Create(wxWindow *parent, wxWindowID id,
     return QtCreateControl( parent, id, pos, size, style, wxDefaultValidator, name );
 }
 
-QGroupBox *wxStaticBox::GetHandle() const
+QWidget *wxStaticBox::GetHandle() const
 {
     return m_qtGroupBox;
 }
diff --git a/src/qt/statline.cpp b/src/qt/statline.cpp
index 0e0227904b..444f59c6e7 100644
--- a/src/qt/statline.cpp
+++ b/src/qt/statline.cpp
@@ -10,6 +10,8 @@
 
 #include "wx/statline.h"
 
+#include <QtWidgets/QFrame>
+
 wxStaticLine::wxStaticLine()
 {
 }
@@ -40,7 +42,7 @@ bool wxStaticLine::Create( wxWindow *parent,
     return QtCreateControl( parent, id, pos, size, style, wxDefaultValidator, name );
 }
 
-QFrame *wxStaticLine::GetHandle() const
+QWidget *wxStaticLine::GetHandle() const
 {
     return m_qtFrame;
 }
diff --git a/src/qt/stattext.cpp b/src/qt/stattext.cpp
index eed8c97515..c60a6fdd36 100644
--- a/src/qt/stattext.cpp
+++ b/src/qt/stattext.cpp
@@ -12,6 +12,8 @@
 #include "wx/qt/private/converter.h"
 #include "wx/qt/private/winevent.h"
 
+#include <QtWidgets/QLabel>
+
 class wxQtStaticText : public wxQtEventSignalHandler< QLabel, wxStaticText >
 {
 public:
@@ -60,7 +62,7 @@ void wxStaticText::SetLabel(const wxString& label)
     m_qtLabel->setText( wxQtConvertString( label ) );
 }
 
-QLabel *wxStaticText::GetHandle() const
+QWidget *wxStaticText::GetHandle() const
 {
     return m_qtLabel;
 }
diff --git a/src/qt/statusbar.cpp b/src/qt/statusbar.cpp
index 4056fbfb13..8b0f052628 100644
--- a/src/qt/statusbar.cpp
+++ b/src/qt/statusbar.cpp
@@ -13,6 +13,8 @@
 #include "wx/qt/private/converter.h"
 #include "wx/qt/private/winevent.h"
 
+#include <QtWidgets/QStatusBar>
+#include <QtWidgets/QLabel>
 
 class wxQtStatusBar : public wxQtEventSignalHandler< QStatusBar, wxStatusBar >
 {
@@ -28,10 +30,17 @@ wxQtStatusBar::wxQtStatusBar( wxWindow *parent, wxStatusBar *handler )
 
 //==============================================================================
 
+
+wxStatusBar::wxStatusBar()
+{
+    Init();
+}
+
 wxStatusBar::wxStatusBar(wxWindow *parent, wxWindowID winid,
             long style,
             const wxString& name)
 {
+    Init();
     Create( parent, winid, style, name );
 }
 
@@ -41,6 +50,7 @@ bool wxStatusBar::Create(wxWindow *parent, wxWindowID WXUNUSED(winid),
     wxMISSING_IMPLEMENTATION( "wxStatusBar::Create parameters" );
 
     m_qtStatusBar = new wxQtStatusBar( parent, this );
+    m_qtPanes = new QList < QLabel* >;
 
     if(style & wxSTB_SIZEGRIP)
         m_qtStatusBar->setSizeGripEnabled(true);
@@ -57,7 +67,7 @@ bool wxStatusBar::GetFieldRect(int i, wxRect& rect) const
     wxCHECK_MSG( (i >= 0) && ((size_t)i < m_panes.GetCount()), false,
                  "invalid statusbar field index" );
 
-    rect = wxQtConvertRect(m_qtPanes[i]->geometry());
+    rect = wxQtConvertRect((*m_qtPanes)[i]->geometry());
     return true;
 }
 
@@ -78,7 +88,7 @@ int wxStatusBar::GetBorderY() const
 
 void wxStatusBar::DoUpdateStatusText(int number)
 {
-    m_qtPanes[number]->setText( wxQtConvertString( m_panes[number].GetText() ) );
+    (*m_qtPanes)[number]->setText( wxQtConvertString( m_panes[number].GetText() ) );
 }
 
 // Called each time number/size of panes changes
@@ -89,14 +99,20 @@ void wxStatusBar::Refresh( bool eraseBackground, const wxRect *rect )
     wxWindow::Refresh( eraseBackground, rect );
 }
 
+void wxStatusBar::Init()
+{
+    m_qtPanes = NULL;
+}
+
+
 void wxStatusBar::UpdateFields()
 {
     // is it a good idea to recreate all the panes every update?
 
-    while ( !m_qtPanes.isEmpty() )
+    while ( !m_qtPanes->isEmpty() )
     {
         //Remove all panes
-        delete m_qtPanes.takeLast();
+        delete m_qtPanes->takeLast();
     }
 
     for (size_t i = 0; i < m_panes.GetCount(); i++)
@@ -105,7 +121,7 @@ void wxStatusBar::UpdateFields()
         int width = m_panes[i].GetWidth();
 
         QLabel *pane = new QLabel( m_qtStatusBar );
-        m_qtPanes.append( pane );
+        m_qtPanes->append( pane );
 
         if ( width >= 0 )
         {
@@ -120,7 +136,7 @@ void wxStatusBar::UpdateFields()
     }
 }
 
-QStatusBar *wxStatusBar::GetHandle() const
+QWidget *wxStatusBar::GetHandle() const
 {
     return m_qtStatusBar;
 }
diff --git a/src/qt/taskbar.cpp b/src/qt/taskbar.cpp
index 6b40fe8507..b375afd79f 100644
--- a/src/qt/taskbar.cpp
+++ b/src/qt/taskbar.cpp
@@ -10,6 +10,8 @@
 
 #include "wx/taskbar.h"
 
+#include <QtWidgets/QSystemTrayIcon>
+
 //=============================================================================
 
 bool wxTaskBarIconBase::IsAvailable()
@@ -23,6 +25,12 @@ wxIMPLEMENT_DYNAMIC_CLASS(wxTaskBarIcon, wxTaskBarIconBase);
 
 wxTaskBarIcon::wxTaskBarIcon(wxTaskBarIconType WXUNUSED(iconType))
 {
+    m_qtSystemTrayIcon = new QSystemTrayIcon;
+}
+
+wxTaskBarIcon::~wxTaskBarIcon()
+{
+    delete m_qtSystemTrayIcon;
 }
 
 bool wxTaskBarIcon::SetIcon(const wxIcon& WXUNUSED(icon),
diff --git a/src/qt/textctrl.cpp b/src/qt/textctrl.cpp
index 166edff9ff..2313df841a 100644
--- a/src/qt/textctrl.cpp
+++ b/src/qt/textctrl.cpp
@@ -14,6 +14,9 @@
 #include "wx/qt/private/winevent.h"
 #include "wx/qt/private/utils.h"
 
+#include <QtWidgets/QLineEdit>
+#include <QtWidgets/QTextEdit>
+
 class wxQtLineEdit : public wxQtEventSignalHandler< QLineEdit, wxTextCtrl >
 {
 public:
diff --git a/src/qt/tglbtn.cpp b/src/qt/tglbtn.cpp
index d89eb54134..f27c72490c 100644
--- a/src/qt/tglbtn.cpp
+++ b/src/qt/tglbtn.cpp
@@ -21,6 +21,8 @@
 #include "wx/qt/private/converter.h"
 #include "wx/qt/private/winevent.h"
 
+#include <QtWidgets/QPushButton>
+
 class wxQtToggleButton : public wxQtEventSignalHandler< QPushButton, wxAnyButton >
 {
 
@@ -94,7 +96,7 @@ bool wxBitmapToggleButton::GetValue() const
     return m_qtPushButton->isChecked();
 }
 
-QPushButton *wxBitmapToggleButton::GetHandle() const
+QWidget *wxBitmapToggleButton::GetHandle() const
 {
     return m_qtPushButton;
 }
@@ -144,7 +146,7 @@ bool wxToggleButton::GetValue() const
     return m_qtPushButton->isChecked();
 }
 
-QPushButton *wxToggleButton::GetHandle() const
+QWidget *wxToggleButton::GetHandle() const
 {
     return m_qtPushButton;
 }
diff --git a/src/qt/timer.cpp b/src/qt/timer.cpp
index 3b52a44b02..4c991a3549 100644
--- a/src/qt/timer.cpp
+++ b/src/qt/timer.cpp
@@ -10,7 +10,7 @@
 
 #if wxUSE_TIMER
 
-#include "wx/qt/timer.h"
+#include "wx/qt/private/timer.h"
 #include <QtCore/QTimerEvent>
 
 wxQtTimerImpl::wxQtTimerImpl( wxTimer* timer )
diff --git a/src/qt/toolbar.cpp b/src/qt/toolbar.cpp
index 5704942d10..cad52f82cb 100644
--- a/src/qt/toolbar.cpp
+++ b/src/qt/toolbar.cpp
@@ -25,6 +25,8 @@
 #include "wx/qt/private/winevent.h"
 #include "wx/qt/private/converter.h"
 
+#include <QtWidgets/QToolBar>
+
 class wxQtToolButton;
 class wxToolBarTool : public wxToolBarToolBase
 {
@@ -144,7 +146,7 @@ wxQtToolbar::wxQtToolbar( wxWindow *parent, wxToolBar *handler )
 }
 
 
-QToolBar *wxToolBar::GetHandle() const
+QWidget *wxToolBar::GetHandle() const
 {
     return m_qtToolBar;
 }
@@ -192,7 +194,7 @@ void wxToolBar::SetWindowStyleFlag( long style )
 
     m_qtToolBar->setOrientation( IsVertical() ? Qt::Vertical : Qt::Horizontal);
 
-    Qt::ToolButtonStyle buttonStyle = GetButtonStyle();
+    Qt::ToolButtonStyle buttonStyle = (Qt::ToolButtonStyle)GetButtonStyle();
 
     // bring the initial state of all the toolbar items in line with the
     for ( wxToolBarToolsList::const_iterator i = m_tools.begin();
@@ -235,11 +237,11 @@ QActionGroup* wxToolBar::GetActionGroup(size_t pos)
 {
     QActionGroup *actionGroup = NULL;
     if (pos > 0)
-        actionGroup = GetHandle()->actions().at(pos-1)->actionGroup();
-    if (actionGroup == NULL && (int)pos < GetHandle()->actions().size() - 1)
-        actionGroup = GetHandle()->actions().at(pos+1)->actionGroup();
+        actionGroup = m_qtToolBar->actions().at(pos-1)->actionGroup();
+    if (actionGroup == NULL && (int)pos < m_qtToolBar->actions().size() - 1)
+        actionGroup = m_qtToolBar->actions().at(pos+1)->actionGroup();
     if (actionGroup == NULL)
-        actionGroup = new QActionGroup(GetHandle());
+        actionGroup = new QActionGroup(m_qtToolBar);
     return actionGroup;
 }
 
@@ -247,15 +249,15 @@ bool wxToolBar::DoInsertTool(size_t pos, wxToolBarToolBase *toolBase)
 {
     wxToolBarTool* tool = static_cast<wxToolBarTool*>(toolBase);
     QAction *before = NULL;
-    if (pos >= 0 && pos < (size_t)GetHandle()->actions().size())
-        before = GetHandle()->actions().at(pos);
+    if (pos >= 0 && pos < (size_t)m_qtToolBar->actions().size())
+        before = m_qtToolBar->actions().at(pos);
 
     QAction *action;
     switch ( tool->GetStyle() )
     {
         case wxTOOL_STYLE_BUTTON:
             tool->m_qtToolButton = new wxQtToolButton(this, tool);
-            tool->m_qtToolButton->setToolButtonStyle(GetButtonStyle());
+            tool->m_qtToolButton->setToolButtonStyle((Qt::ToolButtonStyle)GetButtonStyle());
             tool->SetLabel( tool->GetLabel() );
 
             if (!HasFlag(wxTB_NOICONS))
@@ -263,7 +265,7 @@ bool wxToolBar::DoInsertTool(size_t pos, wxToolBarToolBase *toolBase)
             if (!HasFlag(wxTB_NO_TOOLTIPS))
                 tool->SetToolTip();
 
-            action = GetHandle()->insertWidget(before, tool->m_qtToolButton);
+            action = m_qtToolBar->insertWidget(before, tool->m_qtToolButton);
 
             switch (tool->GetKind())
             {
@@ -285,14 +287,14 @@ bool wxToolBar::DoInsertTool(size_t pos, wxToolBarToolBase *toolBase)
             if (tool->IsStretchable()) {
                 QWidget* spacer = new QWidget();
                 spacer->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
-                GetHandle()->insertWidget(before, spacer);
+                m_qtToolBar->insertWidget(before, spacer);
             } else
-                GetHandle()->insertSeparator(before);
+                m_qtToolBar->insertSeparator(before);
             break;
 
         case wxTOOL_STYLE_CONTROL:
             wxWindow* control = tool->GetControl();
-            GetHandle()->insertWidget(before, control->GetHandle());
+            m_qtToolBar->insertWidget(before, control->GetHandle());
             break;
     }
 
@@ -344,7 +346,7 @@ wxToolBarToolBase *wxToolBar::CreateTool(wxControl *control,
     return new wxToolBarTool(this, control, label);
 }
 
-Qt::ToolButtonStyle wxToolBar::GetButtonStyle()
+long wxToolBar::GetButtonStyle()
 {
     if (!HasFlag(wxTB_NOICONS)) {
         if (HasFlag(wxTB_HORZ_LAYOUT))
diff --git a/src/qt/toplevel.cpp b/src/qt/toplevel.cpp
index a5c2466e48..79969cc52d 100644
--- a/src/qt/toplevel.cpp
+++ b/src/qt/toplevel.cpp
@@ -11,6 +11,7 @@
 #include "wx/toplevel.h"
 #include "wx/qt/private/converter.h"
 #include <QtGui/QIcon>
+#include <QtWidgets/QWidget>
 
 wxTopLevelWindowQt::wxTopLevelWindowQt()
 {
diff --git a/src/qt/treectrl.cpp b/src/qt/treectrl.cpp
index 2362c6d99d..f73a202612 100644
--- a/src/qt/treectrl.cpp
+++ b/src/qt/treectrl.cpp
@@ -10,6 +10,8 @@
 
 #include "wx/treectrl.h"
 
+#include <QtWidgets/QTreeWidget>
+
 wxTreeCtrl::wxTreeCtrl()
 {
 }
@@ -348,7 +350,7 @@ wxTreeItemId wxTreeCtrl::DoTreeHitTest(const wxPoint& point, int& flags) const
     return wxTreeItemId();
 }
 
-QTreeWidget *wxTreeCtrl::GetHandle() const
+QWidget *wxTreeCtrl::GetHandle() const
 {
     return m_qtTreeWidget;
 }
diff --git a/src/qt/window.cpp b/src/qt/window.cpp
index b29cd08531..07295d7591 100644
--- a/src/qt/window.cpp
+++ b/src/qt/window.cpp
@@ -18,6 +18,8 @@
 #include <QtWidgets/QApplication>
 #include <QtWidgets/QWidget>
 #include <QtWidgets/QScrollArea>
+#include <QtWidgets/QMenu>
+#include <QtWidgets/QShortcut>
 
 #ifndef WX_PRECOMP
     #include "wx/dcclient.h"
@@ -150,6 +152,7 @@ void wxWindowQt::Init()
 #if wxUSE_ACCEL
     m_qtShortcutHandler = new wxQtShortcutHandler( this );
     m_processingShortcut = false;
+    m_qtShortcuts = NULL;
 #endif
     m_qtWindow = NULL;
     m_qtContainer = NULL;
@@ -185,6 +188,7 @@ wxWindowQt::~wxWindowQt()
 
 #if wxUSE_ACCEL
     m_qtShortcutHandler->deleteLater();
+    delete m_qtShortcuts;
 #endif
 
     // Delete only if the qt widget was created or assigned to this base class
@@ -505,7 +509,7 @@ wxScrollBar *wxWindowQt::QtGetScrollBar( int orientation ) const
  * passed as parameter */
 wxScrollBar *wxWindowQt::QtSetScrollBar( int orientation, wxScrollBar *scrollBar )
 {
-    QAbstractScrollArea *scrollArea = QtGetScrollBarsContainer();
+    QScrollArea *scrollArea = QtGetScrollBarsContainer();
     wxCHECK_MSG( scrollArea, NULL, "Window without scrolling area" );
 
     // Create a new scrollbar if needed
@@ -529,12 +533,12 @@ wxScrollBar *wxWindowQt::QtSetScrollBar( int orientation, wxScrollBar *scrollBar
     // Let Qt handle layout
     if ( orientation == wxHORIZONTAL )
     {
-        scrollArea->setHorizontalScrollBar( scrollBar->GetHandle() );
+        scrollArea->setHorizontalScrollBar( scrollBar->GetQScrollBar() );
         m_horzScrollBar = scrollBar;
     }
     else
     {
-        scrollArea->setVerticalScrollBar( scrollBar->GetHandle() );
+        scrollArea->setVerticalScrollBar( scrollBar->GetQScrollBar() );
         m_vertScrollBar = scrollBar;
     }
     return scrollBar;
@@ -932,15 +936,16 @@ void wxWindowQt::SetAcceleratorTable( const wxAcceleratorTable& accel )
     wxWindowBase::SetAcceleratorTable( accel );
 
     // Disable previously set accelerators
-    while ( !m_qtShortcuts.isEmpty() )
-        delete m_qtShortcuts.takeFirst();
+    while ( !m_qtShortcuts->isEmpty() )
+        delete m_qtShortcuts->takeFirst();
 
     // Create new shortcuts (use GetHandle() so all events inside
     // the window are handled, not only in the container subwindow)
+    delete m_qtShortcuts;
     m_qtShortcuts = accel.ConvertShortcutTable( GetHandle() );
 
     // Connect shortcuts to window
-    Q_FOREACH( QShortcut *s, m_qtShortcuts )
+    Q_FOREACH( QShortcut *s, *m_qtShortcuts )
     {
         QObject::connect( s, &QShortcut::activated, m_qtShortcutHandler, &wxQtShortcutHandler::activated );
         QObject::connect( s, &QShortcut::activatedAmbiguously, m_qtShortcutHandler, &wxQtShortcutHandler::activated );
@@ -1470,7 +1475,7 @@ QWidget *wxWindowQt::GetHandle() const
     return m_qtWindow;
 }
 
-QAbstractScrollArea *wxWindowQt::QtGetScrollBarsContainer() const
+QScrollArea *wxWindowQt::QtGetScrollBarsContainer() const
 {
     return m_qtContainer;
 }