diff --git a/configure b/configure
index 7725b68fb5..49e5978fa5 100755
--- a/configure
+++ b/configure
@@ -971,6 +971,8 @@ Xxf86vm_LIBS
 Xxf86vm_CFLAGS
 Xinerama_LIBS
 Xinerama_CFLAGS
+QT5_LIBS
+QT5_CFLAGS
 PANGOFT2_LIBS
 PANGOFT2_CFLAGS
 PANGOXFT_LIBS
@@ -1375,6 +1377,8 @@ PANGOXFT_CFLAGS
 PANGOXFT_LIBS
 PANGOFT2_CFLAGS
 PANGOFT2_LIBS
+QT5_CFLAGS
+QT5_LIBS
 Xinerama_CFLAGS
 Xinerama_LIBS
 Xxf86vm_CFLAGS
@@ -2355,6 +2359,8 @@ Some influential environment variables:
               C compiler flags for PANGOFT2, overriding pkg-config
   PANGOFT2_LIBS
               linker flags for PANGOFT2, overriding pkg-config
+  QT5_CFLAGS  C compiler flags for QT5, overriding pkg-config
+  QT5_LIBS    linker flags for QT5, overriding pkg-config
   Xinerama_CFLAGS
               C compiler flags for Xinerama, overriding pkg-config
   Xinerama_LIBS
@@ -25242,15 +25248,208 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 
     if test "$wxUSE_QT" = 1; then
-        TOOLKIT=QT
-        GUIDIST=QT_DIST
-        TOOLKIT_DIR="qt"
-        TOOLKIT_INCLUDE="${TOOLKIT_INCLUDE} `pkg-config Qt5Core Qt5Widgets Qt5Gui Qt5OpenGL Qt5Test --cflags` -DQT_WIDGETS_LIB"
-        GUI_TK_LIBRARY="${GUI_TK_LIBRARY} `pkg-config Qt5Core Qt5Widgets Qt5Gui Qt5OpenGL Qt5Test --libs`"
-        if `pkg-config --variable qt_config Qt5Core | grep "reduce_relocations" >/dev/null`; then
-                        SAMPLES_CXXFLAGS="-fPIC $SAMPLES_CXXFLAGS"
-            WXCONFIG_CXXFLAGS="-fPIC $WXCONFIG_CXXFLAGS $TOOLKIT_INCLUDE"
+
+
+if test "x$ac_cv_env_PKG_CONFIG_set" != "xset"; then
+	if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}pkg-config", so it can be a program name with args.
+set dummy ${ac_tool_prefix}pkg-config; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_path_PKG_CONFIG+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  case $PKG_CONFIG in
+  [\\/]* | ?:[\\/]*)
+  ac_cv_path_PKG_CONFIG="$PKG_CONFIG" # Let the user override the test with a path.
+  ;;
+  *)
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_path_PKG_CONFIG="$as_dir/$ac_word$ac_exec_ext"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+  ;;
+esac
+fi
+PKG_CONFIG=$ac_cv_path_PKG_CONFIG
+if test -n "$PKG_CONFIG"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $PKG_CONFIG" >&5
+$as_echo "$PKG_CONFIG" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_path_PKG_CONFIG"; then
+  ac_pt_PKG_CONFIG=$PKG_CONFIG
+  # Extract the first word of "pkg-config", so it can be a program name with args.
+set dummy pkg-config; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_path_ac_pt_PKG_CONFIG+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  case $ac_pt_PKG_CONFIG in
+  [\\/]* | ?:[\\/]*)
+  ac_cv_path_ac_pt_PKG_CONFIG="$ac_pt_PKG_CONFIG" # Let the user override the test with a path.
+  ;;
+  *)
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_path_ac_pt_PKG_CONFIG="$as_dir/$ac_word$ac_exec_ext"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+  ;;
+esac
+fi
+ac_pt_PKG_CONFIG=$ac_cv_path_ac_pt_PKG_CONFIG
+if test -n "$ac_pt_PKG_CONFIG"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_pt_PKG_CONFIG" >&5
+$as_echo "$ac_pt_PKG_CONFIG" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+  if test "x$ac_pt_PKG_CONFIG" = x; then
+    PKG_CONFIG=""
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    PKG_CONFIG=$ac_pt_PKG_CONFIG
+  fi
+else
+  PKG_CONFIG="$ac_cv_path_PKG_CONFIG"
+fi
+
+fi
+if test -n "$PKG_CONFIG"; then
+	_pkg_min_version=0.9.0
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking pkg-config is at least version $_pkg_min_version" >&5
+$as_echo_n "checking pkg-config is at least version $_pkg_min_version... " >&6; }
+	if $PKG_CONFIG --atleast-pkgconfig-version $_pkg_min_version; then
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+	else
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+		PKG_CONFIG=""
+	fi
+
+fi
+
+
+pkg_failed=no
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for QT5" >&5
+$as_echo_n "checking for QT5... " >&6; }
+
+if test -n "$PKG_CONFIG"; then
+    if test -n "$QT5_CFLAGS"; then
+        pkg_cv_QT5_CFLAGS="$QT5_CFLAGS"
+    else
+        if test -n "$PKG_CONFIG" && \
+    { { $as_echo "$as_me:${as_lineno-$LINENO}: \$PKG_CONFIG --exists --print-errors \"Qt5Core Qt5Widgets Qt5Gui Qt5OpenGL Qt5Test\""; } >&5
+  ($PKG_CONFIG --exists --print-errors "Qt5Core Qt5Widgets Qt5Gui Qt5OpenGL Qt5Test") 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+  pkg_cv_QT5_CFLAGS=`$PKG_CONFIG --cflags "Qt5Core Qt5Widgets Qt5Gui Qt5OpenGL Qt5Test" 2>/dev/null`
+else
+  pkg_failed=yes
+fi
+    fi
+else
+	pkg_failed=untried
+fi
+if test -n "$PKG_CONFIG"; then
+    if test -n "$QT5_LIBS"; then
+        pkg_cv_QT5_LIBS="$QT5_LIBS"
+    else
+        if test -n "$PKG_CONFIG" && \
+    { { $as_echo "$as_me:${as_lineno-$LINENO}: \$PKG_CONFIG --exists --print-errors \"Qt5Core Qt5Widgets Qt5Gui Qt5OpenGL Qt5Test\""; } >&5
+  ($PKG_CONFIG --exists --print-errors "Qt5Core Qt5Widgets Qt5Gui Qt5OpenGL Qt5Test") 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+  pkg_cv_QT5_LIBS=`$PKG_CONFIG --libs "Qt5Core Qt5Widgets Qt5Gui Qt5OpenGL Qt5Test" 2>/dev/null`
+else
+  pkg_failed=yes
+fi
+    fi
+else
+	pkg_failed=untried
+fi
+
+
+
+if test $pkg_failed = yes; then
+
+if $PKG_CONFIG --atleast-pkgconfig-version 0.20; then
+        _pkg_short_errors_supported=yes
+else
+        _pkg_short_errors_supported=no
+fi
+        if test $_pkg_short_errors_supported = yes; then
+	        QT5_PKG_ERRORS=`$PKG_CONFIG --short-errors --errors-to-stdout --print-errors "Qt5Core Qt5Widgets Qt5Gui Qt5OpenGL Qt5Test"`
+        else
+	        QT5_PKG_ERRORS=`$PKG_CONFIG --errors-to-stdout --print-errors "Qt5Core Qt5Widgets Qt5Gui Qt5OpenGL Qt5Test"`
         fi
+	# Put the nasty error message in config.log where it belongs
+	echo "$QT5_PKG_ERRORS" >&5
+
+
+                as_fn_error $? "Qt5 libraries are not available" "$LINENO" 5
+
+
+elif test $pkg_failed = untried; then
+
+                as_fn_error $? "Qt5 libraries are not available" "$LINENO" 5
+
+
+else
+	QT5_CFLAGS=$pkg_cv_QT5_CFLAGS
+	QT5_LIBS=$pkg_cv_QT5_LIBS
+        { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+
+                TOOLKIT=QT
+                GUIDIST=QT_DIST
+                TOOLKIT_DIR="qt"
+                TOOLKIT_INCLUDE="${TOOLKIT_INCLUDE} ${QT5_CFLAGS}"
+                GUI_TK_LIBRARY="${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"
+                fi
+
+fi
     fi
         TOOLKIT_DIR=`echo ${TOOLKIT} | tr '[A-Z]' '[a-z]'`
 
@@ -40907,3 +41106,4 @@ echo "                                       libmspack          ${wxUSE_LIBMSPAC
 echo "                                       sdl                ${wxUSE_LIBSDL}"
 
 echo ""
+
diff --git a/configure.in b/configure.in
index 6ff278de70..3971754689 100644
--- a/configure.in
+++ b/configure.in
@@ -3283,16 +3283,26 @@ libraries returned by 'pkg-config gtk+-2.0 --libs' or 'gtk-config
 
 
     if test "$wxUSE_QT" = 1; then
-        TOOLKIT=QT
-        GUIDIST=QT_DIST
-        TOOLKIT_DIR="qt"
-        TOOLKIT_INCLUDE="${TOOLKIT_INCLUDE} `pkg-config Qt5Core Qt5Widgets Qt5Gui Qt5OpenGL Qt5Test --cflags` -DQT_WIDGETS_LIB"
-        GUI_TK_LIBRARY="${GUI_TK_LIBRARY} `pkg-config Qt5Core Qt5Widgets Qt5Gui Qt5OpenGL Qt5Test --libs`"
-        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 $TOOLKIT_INCLUDE"
-        fi
+        PKG_PROG_PKG_CONFIG()
+
+        PKG_CHECK_MODULES(QT5,
+                          [Qt5Core Qt5Widgets Qt5Gui Qt5OpenGL Qt5Test],
+            [
+                TOOLKIT=QT
+                GUIDIST=QT_DIST
+                TOOLKIT_DIR="qt"
+                TOOLKIT_INCLUDE="${TOOLKIT_INCLUDE} ${QT5_CFLAGS}"
+                GUI_TK_LIBRARY="${GUI_TK_LIBRARY} ${QT5_LIBS}"
+                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"
+                fi
+            ],
+            [
+                AC_MSG_ERROR([Qt5 libraries are not available])
+            ]
+        )
     fi
     dnl the name of the directory where the files for this toolkit live
     TOOLKIT_DIR=`echo ${TOOLKIT} | tr '[[A-Z]]' '[[a-z]]'`
diff --git a/include/wx/qt/private/winevent.h b/include/wx/qt/private/winevent.h
index 5ca7d466d5..cbda1cc2a2 100644
--- a/include/wx/qt/private/winevent.h
+++ b/include/wx/qt/private/winevent.h
@@ -63,8 +63,6 @@ public:
 
     void HandleDestroyedSignal()
     {
-        wxLogDebug( wxT("%s was destroyed by Qt. pointer=%p"),
-                    QObject::staticMetaObject.className(), this );
     }
 
     virtual Handler *GetHandler() const
@@ -72,9 +70,6 @@ public:
         // Only process the signal / event if the wxWindow is not destroyed
         if ( !wxWindow::QtRetrieveWindowPointer( this ) )
         {
-            wxLogDebug( wxT("%s win pointer is NULL (wxWindow is deleted)!"),
-                        Widget::staticMetaObject.className()
-                        );
             return NULL;
         }
         else
@@ -90,9 +85,9 @@ protected:
     virtual void changeEvent ( QEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::changeEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandleChangeEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandleChangeEvent(this, event) )
             Widget::changeEvent(event);
         else
             event->accept();
@@ -102,9 +97,9 @@ protected:
     virtual void closeEvent ( QCloseEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::closeEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandleCloseEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandleCloseEvent(this, event) )
             Widget::closeEvent(event);
         else
             event->accept();
@@ -114,9 +109,9 @@ protected:
     virtual void contextMenuEvent ( QContextMenuEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::contextMenuEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandleContextMenuEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandleContextMenuEvent(this, event) )
             Widget::contextMenuEvent(event);
         else
             event->accept();
@@ -129,9 +124,9 @@ protected:
     virtual void enterEvent ( QEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::enterEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandleEnterEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandleEnterEvent(this, event) )
             Widget::enterEvent(event);
         else
             event->accept();
@@ -141,9 +136,9 @@ protected:
     virtual void focusInEvent ( QFocusEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::focusInEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandleFocusEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandleFocusEvent(this, event) )
             Widget::focusInEvent(event);
         else
             event->accept();
@@ -153,9 +148,9 @@ protected:
     virtual void focusOutEvent ( QFocusEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::focusOutEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandleFocusEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandleFocusEvent(this, event) )
             Widget::focusOutEvent(event);
         else
             event->accept();
@@ -165,9 +160,9 @@ protected:
     virtual void hideEvent ( QHideEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::hideEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandleShowEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandleShowEvent(this, event) )
             Widget::hideEvent(event);
         else
             event->accept();
@@ -177,9 +172,9 @@ protected:
     virtual void keyPressEvent ( QKeyEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::keyPressEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandleKeyEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandleKeyEvent(this, event) )
             Widget::keyPressEvent(event);
         else
             event->accept();
@@ -189,9 +184,9 @@ protected:
     virtual void keyReleaseEvent ( QKeyEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::keyReleaseEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandleKeyEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandleKeyEvent(this, event) )
             Widget::keyReleaseEvent(event);
         else
             event->accept();
@@ -201,9 +196,9 @@ protected:
     virtual void leaveEvent ( QEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::leaveEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandleEnterEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandleEnterEvent(this, event) )
             Widget::leaveEvent(event);
         else
             event->accept();
@@ -213,9 +208,9 @@ protected:
     virtual void mouseDoubleClickEvent ( QMouseEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::mouseDoubleClickEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandleMouseEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandleMouseEvent(this, event) )
             Widget::mouseDoubleClickEvent(event);
         else
             event->accept();
@@ -225,9 +220,9 @@ protected:
     virtual void mouseMoveEvent ( QMouseEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::mouseMoveEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandleMouseEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandleMouseEvent(this, event) )
             Widget::mouseMoveEvent(event);
         else
             event->accept();
@@ -237,9 +232,9 @@ protected:
     virtual void mousePressEvent ( QMouseEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::mousePressEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandleMouseEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandleMouseEvent(this, event) )
             Widget::mousePressEvent(event);
         else
             event->accept();
@@ -249,9 +244,9 @@ protected:
     virtual void mouseReleaseEvent ( QMouseEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::mouseReleaseEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandleMouseEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandleMouseEvent(this, event) )
             Widget::mouseReleaseEvent(event);
         else
             event->accept();
@@ -261,9 +256,9 @@ protected:
     virtual void moveEvent ( QMoveEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::moveEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandleMoveEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandleMoveEvent(this, event) )
             Widget::moveEvent(event);
         else
             event->accept();
@@ -273,9 +268,9 @@ protected:
     virtual void paintEvent ( QPaintEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::paintEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandlePaintEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandlePaintEvent(this, event) )
             Widget::paintEvent(event);
         else
             event->accept();
@@ -285,9 +280,9 @@ protected:
     virtual void resizeEvent ( QResizeEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::resizeEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandleResizeEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandleResizeEvent(this, event) )
             Widget::resizeEvent(event);
         else
             event->accept();
@@ -297,9 +292,9 @@ protected:
     virtual void showEvent ( QShowEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::showEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandleShowEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandleShowEvent(this, event) )
             Widget::showEvent(event);
         else
             event->accept();
@@ -309,9 +304,9 @@ protected:
     virtual void wheelEvent ( QWheelEvent * event )
     {
         if ( !this->GetHandler() )
-            wxLogDebug( wxT("%s::wheelEvent for invalid handler!"),
-                        Widget::staticMetaObject.className() );
-        else if ( !this->GetHandler()->QtHandleWheelEvent(this, event) )
+            return;
+
+        if ( !this->GetHandler()->QtHandleWheelEvent(this, event) )
             Widget::wheelEvent(event);
         else
             event->accept();
diff --git a/src/qt/bitmap.cpp b/src/qt/bitmap.cpp
index 60417f44bf..b45171442d 100644
--- a/src/qt/bitmap.cpp
+++ b/src/qt/bitmap.cpp
@@ -22,6 +22,7 @@
 #endif // WX_PRECOMP
 
 #include "wx/bitmap.h"
+#include "wx/cursor.h"
 #include "wx/rawbmp.h"
 #include "wx/qt/private/converter.h"
 #include "wx/qt/private/utils.h"
diff --git a/src/qt/checkbox.cpp b/src/qt/checkbox.cpp
index 537daa4281..5196b684bd 100644
--- a/src/qt/checkbox.cpp
+++ b/src/qt/checkbox.cpp
@@ -119,6 +119,9 @@ wxCheckBoxState wxCheckBox::DoGet3StateValue() const
     case Qt::PartiallyChecked:
         return wxCHK_UNDETERMINED;
     }
+
+    wxFAIL_MSG( "unknown QCheckBox state" );
+    return wxCHK_UNDETERMINED;
 }
 
 QCheckBox *wxCheckBox::GetHandle() const
diff --git a/src/qt/dc.cpp b/src/qt/dc.cpp
index 05ac9f5988..d1996b553f 100644
--- a/src/qt/dc.cpp
+++ b/src/qt/dc.cpp
@@ -409,9 +409,6 @@ void wxQtDCImpl::DoSetDeviceClippingRegion(const wxRegion& region)
         QTransform qtrans = m_qtPainter->worldTransform();
         // Reset transofrmation to match device coordinates
         m_qtPainter->setWorldTransform( QTransform() );
-        wxLogDebug(wxT("wxQtDCImpl::DoSetDeviceClippingRegion rect %d %d %d %d"),
-                   qregion.boundingRect().x(), qregion.boundingRect().y(),
-                   qregion.boundingRect().width(), qregion.boundingRect().height());
         // Set QPainter clipping (intersection if not the first one)
         m_qtPainter->setClipRegion( qregion,
                                  m_clipping ? Qt::IntersectClip : Qt::ReplaceClip );
diff --git a/src/qt/dcclient.cpp b/src/qt/dcclient.cpp
index 3b8dfce898..0a69244bfd 100644
--- a/src/qt/dcclient.cpp
+++ b/src/qt/dcclient.cpp
@@ -102,9 +102,6 @@ wxClientDCImpl::~wxClientDCImpl()
             {
                 // only force the update of the rect affected by the DC
                 widget->repaint( rect );
-                wxLogDebug( wxT("wxClientDC Repainting %s (%d %d %d %d)"),
-                           (const char*) m_window->GetName(),
-                           rect.left(), rect.top(), rect.width(), rect.height());
             }
             else
             {
diff --git a/src/qt/dcscreen.cpp b/src/qt/dcscreen.cpp
index d3986fdca7..b6e2adfc0f 100644
--- a/src/qt/dcscreen.cpp
+++ b/src/qt/dcscreen.cpp
@@ -13,6 +13,7 @@
 
 #include <QtWidgets/QDesktopWidget>
 #include <QtGui/QScreen>
+#include <QApplication>
 #include <QPixmap>
 
 wxIMPLEMENT_ABSTRACT_CLASS(wxScreenDCImpl, wxWindowDCImpl);
diff --git a/src/qt/uiaction.cpp b/src/qt/uiaction.cpp
index 127843440e..c3d6261fcd 100644
--- a/src/qt/uiaction.cpp
+++ b/src/qt/uiaction.cpp
@@ -13,6 +13,8 @@
 #endif
 
 #include <QtTest/QtTestGui>
+#include <QApplication>
+#include <QWidget>
 
 #include "wx/qt/defs.h"
 #include "wx/qt/private/utils.h"
@@ -25,6 +27,16 @@
 using namespace Qt;
 using namespace QTest;
 
+// Apparently {mouse,key}Event() functions signature has changed somewhere
+// between Qt 5.3 and 5.5 as they're documented to take QWidget in the latter
+// but actually take QWindow in the former, so use this helper to hide the
+// difference.
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 5, 0))
+inline QWidget* argForEvents(QWidget* w) { return w; }
+#else
+inline QWindow* argForEvents(QWidget* w) { return w->windowHandle(); }
+#endif
+
 static MouseButton ConvertMouseButton( int button )
 {
     MouseButton qtButton;
@@ -65,7 +77,7 @@ static bool SimulateMouseButton( MouseAction mouseAction, MouseButton mouseButto
     QPoint mousePosition = QCursor::pos();
     QWidget *widget = QApplication::widgetAt( mousePosition );
     if ( widget != NULL )
-        mouseEvent( mouseAction, widget, mouseButton, NoModifier, mousePosition );
+        mouseEvent( mouseAction, argForEvents(widget), mouseButton, NoModifier, mousePosition );
 
     // If we found a widget then we successfully simulated an event:
 
@@ -76,7 +88,7 @@ static bool SimulateKeyboardKey( KeyAction keyAction, Key key )
 {
     QWidget *widget = QApplication::focusWidget();
     if ( widget != NULL )
-        keyEvent( keyAction, widget, key );
+        keyEvent( keyAction, argForEvents(widget), key );
 
     // If we found a widget then we successfully simulated an event:
 
diff --git a/src/qt/window.cpp b/src/qt/window.cpp
index 1db35744b5..6c59620127 100644
--- a/src/qt/window.cpp
+++ b/src/qt/window.cpp
@@ -37,6 +37,8 @@
 #define VERT_SCROLLBAR_POSITION 0, 1
 #define HORZ_SCROLLBAR_POSITION 1, 0
 
+#define TRACE_QT_WINDOW "qtwindow"
+
 // Base Widget helper (no scrollbar, used by wxWindow)
 
 class wxQtWidget : public wxQtEventSignalHandler< QWidget, wxWindowQt >
@@ -188,7 +190,7 @@ wxWindowQt::~wxWindowQt()
     // Delete only if the qt widget was created or assigned to this base class
     if (m_qtWindow)
     {
-        wxLogDebug(wxT("wxWindow::~wxWindow %s m_qtWindow=%p"),
+        wxLogTrace(TRACE_QT_WINDOW, wxT("wxWindow::~wxWindow %s m_qtWindow=%p"),
                    (const char*)GetName(), m_qtWindow);
         // Avoid sending further signals (i.e. if deleting the current page)
         m_qtWindow->blockSignals(true);
@@ -200,7 +202,7 @@ wxWindowQt::~wxWindowQt()
     }
     else
     {
-        wxLogDebug(wxT("wxWindow::~wxWindow %s m_qtWindow is NULL"),
+        wxLogTrace(TRACE_QT_WINDOW, wxT("wxWindow::~wxWindow %s m_qtWindow is NULL"),
                    (const char*)GetName());
     }
 }
@@ -256,7 +258,7 @@ void wxWindowQt::PostCreation(bool generic)
         // store pointer to the QWidget subclass (to be used in the destructor)
         m_qtWindow = GetHandle();
     }
-    wxLogDebug(wxT("wxWindow::Create %s m_qtWindow=%p"),
+    wxLogTrace(TRACE_QT_WINDOW, wxT("wxWindow::Create %s m_qtWindow=%p"),
                (const char*)GetName(), m_qtWindow);
 
     // set the background style after creation (not before like in wxGTK)
@@ -391,7 +393,7 @@ void wxWindowQt::WarpPointer(int x, int y)
 
 void wxWindowQt::Update()
 {
-    wxLogDebug(wxT("wxWindow::Update %s"), (const char*)GetName());
+    wxLogTrace(TRACE_QT_WINDOW, wxT("wxWindow::Update %s"), (const char*)GetName());
     // send the paint event to the inner widget in scroll areas:
     if ( QtGetScrollBarsContainer() )
     {
@@ -417,14 +419,14 @@ void wxWindowQt::Refresh( bool WXUNUSED( eraseBackground ), const wxRect *rect )
     {
         if ( rect != NULL )
         {
-            wxLogDebug(wxT("wxWindow::Refresh %s rect %d %d %d %d"),
+            wxLogTrace(TRACE_QT_WINDOW, wxT("wxWindow::Refresh %s rect %d %d %d %d"),
                        (const char*)GetName(),
                        rect->x, rect->y, rect->width, rect->height);
             widget->update( wxQtConvertRect( *rect ));
         }
         else
         {
-            wxLogDebug(wxT("wxWindow::Refresh %s"),
+            wxLogTrace(TRACE_QT_WINDOW, wxT("wxWindow::Refresh %s"),
                        (const char*)GetName());
             widget->update();
         }
@@ -1018,13 +1020,6 @@ bool wxWindowQt::QtHandlePaintEvent ( QWidget *handler, QPaintEvent *event )
         // use the Qt event region:
         m_updateRegion.QtSetRegion( event->region() );
 
-        if (false)
-            wxLogDebug(wxT("wxWindow::QtHandlePaintEvent %s %s region %d %d %d %d"),
-                   (const char*)GetName(),
-                   m_qtPicture->isNull() ? "wxPaintDC" : "wxClientDC",
-                   m_updateRegion.GetBox().x, m_updateRegion.GetBox().y,
-                   m_updateRegion.GetBox().width, m_updateRegion.GetBox().height);
-
         // Prepare the Qt painter for wxWindowDC:
         bool ok = false;
         if ( QtGetScrollBarsContainer() )
@@ -1071,7 +1066,7 @@ bool wxWindowQt::QtHandlePaintEvent ( QWidget *handler, QPaintEvent *event )
                             // Ensure DC is cleared if handler didn't and Qt will not do it
                             if ( UseBgCol() && !GetHandle()->autoFillBackground() )
                             {
-                                wxLogDebug(wxT("wxWindow::QtHandlePaintEvent %s clearing DC to %s"),
+                                wxLogTrace(TRACE_QT_WINDOW, wxT("wxWindow::QtHandlePaintEvent %s clearing DC to %s"),
                                            (const char*)GetName(), GetBackgroundColour().GetAsString()
                                            );
                                 dc.SetBackground(GetBackgroundColour());
@@ -1120,7 +1115,7 @@ bool wxWindowQt::QtHandlePaintEvent ( QWidget *handler, QPaintEvent *event )
         else
         {
             // Painter didn't begun, not handled by wxWidgets:
-            wxLogDebug(wxT("wxWindow::QtHandlePaintEvent %s Qt widget painter begin failed"),
+            wxLogTrace(TRACE_QT_WINDOW, wxT("wxWindow::QtHandlePaintEvent %s Qt widget painter begin failed"),
                        (const char*)GetName() );
             return false;
         }