Update generic wxTreeCtrl appearance when theme changes

See #18823

include/wx/generic/treectlg.h

@@ -351,6 +351,10 @@ protected:
     virtual wxSize DoGetBestSize() const wxOVERRIDE;
 
 private:
+    bool m_hasExplicitFont;
+
+    void OnSysColourChanged(wxSysColourChangedEvent&);
+
     // Reset the state of the last find (i.e. keyboard incremental search)
     // operation.
     void ResetFindState();

src/generic/treectlg.cpp

@@ -917,6 +917,7 @@ wxBEGIN_EVENT_TABLE(wxGenericTreeCtrl, wxTreeCtrlBase)
     EVT_SET_FOCUS      (wxGenericTreeCtrl::OnSetFocus)
     EVT_KILL_FOCUS     (wxGenericTreeCtrl::OnKillFocus)
     EVT_TREE_ITEM_GETTOOLTIP(wxID_ANY, wxGenericTreeCtrl::OnGetToolTip)
+    EVT_SYS_COLOUR_CHANGED(wxGenericTreeCtrl::OnSysColourChanged)
 wxEND_EVENT_TABLE()
 
 // -----------------------------------------------------------------------------
@@ -936,24 +937,8 @@ void wxGenericTreeCtrl::Init()
     m_indent = 15;
     m_spacing = 18;
 
-    m_hilightBrush = new wxBrush
+    m_hilightBrush = NULL;
-                         (
+    m_hilightUnfocusedBrush = NULL;
-                            wxSystemSettings::GetColour
-                            (
-                                wxSYS_COLOUR_HIGHLIGHT
-                            ),
-                            wxBRUSHSTYLE_SOLID
-                         );
-
-    m_hilightUnfocusedBrush = new wxBrush
-                              (
-                                 wxSystemSettings::GetColour
-                                 (
-                                     wxSYS_COLOUR_BTNSHADOW
-                                 ),
-                                 wxBRUSHSTYLE_SOLID
-                              );
-
     m_imageListButtons = NULL;
     m_ownsImageListButtons = false;
 
@@ -974,13 +959,6 @@ void wxGenericTreeCtrl::Init()
     m_dndEffectItem = NULL;
 
     m_lastOnSame = false;
-
-#if defined( __WXMAC__ )
-    m_normalFont = wxFont(wxOSX_SYSTEM_FONT_VIEWS);
-#else
-    m_normalFont = wxSystemSettings::GetFont( wxSYS_DEFAULT_GUI_FONT );
-#endif
-    m_boldFont = m_normalFont.Bold();
 }
 
 bool wxGenericTreeCtrl::Create(wxWindow *parent,
@@ -1006,14 +984,9 @@ bool wxGenericTreeCtrl::Create(wxWindow *parent,
         m_spacing = 10;
     }
 
-    wxVisualAttributes attr = GetDefaultAttributes();
+    m_hasExplicitFont = m_hasFont;
-    SetOwnForegroundColour( attr.colFg );
+    wxSysColourChangedEvent evt;
-    SetOwnBackgroundColour( attr.colBg );
+    OnSysColourChanged(evt);
-    if (!m_hasFont)
-        SetOwnFont(attr.font);
-
-    m_dottedPen = wxPen(wxSystemSettings::GetColour(wxSYS_COLOUR_GRAYTEXT),
-                        1, wxPENSTYLE_DOT);
 
     SetInitialSize(size);
 
@@ -1039,6 +1012,29 @@ void wxGenericTreeCtrl::EnableBellOnNoMatch( bool on )
     m_findBell = on;
 }
 
+void wxGenericTreeCtrl::OnSysColourChanged(wxSysColourChangedEvent&)
+{
+    const wxVisualAttributes attr(GetDefaultAttributes());
+    SetOwnForegroundColour(attr.colFg);
+    SetOwnBackgroundColour(attr.colBg);
+    if (!m_hasExplicitFont)
+        SetOwnFont(attr.font);
+
+    delete m_hilightBrush;
+    m_hilightBrush = new wxBrush(wxSystemSettings::GetColour(wxSYS_COLOUR_HIGHLIGHT));
+    delete m_hilightUnfocusedBrush;
+    m_hilightUnfocusedBrush = new wxBrush(wxSystemSettings::GetColour(wxSYS_COLOUR_BTNSHADOW));
+
+    m_dottedPen = wxPen(wxSystemSettings::GetColour(wxSYS_COLOUR_GRAYTEXT), 1, wxPENSTYLE_DOT);
+
+#if defined(__WXOSX__)
+    m_normalFont = wxFont(wxOSX_SYSTEM_FONT_VIEWS);
+#else
+    m_normalFont = wxSystemSettings::GetFont(wxSYS_DEFAULT_GUI_FONT);
+#endif
+    m_boldFont = m_normalFont.Bold();
+}
+
 // -----------------------------------------------------------------------------
 // accessors
 // -----------------------------------------------------------------------------