merged 2.4 branch into the trunk

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@18040 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/univ/window.h

@@ -179,7 +179,7 @@ public:
     // to be used with function above: transparent windows get
     // their background from parents that return TRUE here,
     // so this is mostly for wxPanel, wxTopLevelWindow etc.
-    virtual bool ProvidesBackground() { return FALSE; }
+    virtual bool ProvidesBackground() const { return FALSE; }
 
     // return TRUE if this control can be highlighted when the mouse is over
     // it (the theme decides itself whether it is really highlighted or not)