Make Reparent() work for wxFrame in wxQt

Use the correct parent window, i.e. the one of the central widget and
not of the frame itself.

include/wx/qt/frame.h

@@ -57,6 +57,8 @@ public:
 protected:
     virtual void DoGetClientSize(int *width, int *height) const wxOVERRIDE;
 
+    virtual QWidget* QtGetParentWidget() const wxOVERRIDE;
+
 private:
     // Common part of all ctors.
     void Init()

include/wx/qt/window.h

@@ -215,6 +215,12 @@ protected:
     virtual bool DoPopupMenu(wxMenu *menu, int x, int y) wxOVERRIDE;
 #endif // wxUSE_MENUS
 
+    // Return the parent to use for children being reparented to us: this is
+    // overridden in wxFrame to use its central widget rather than the frame
+    // itself.
+    virtual QWidget* QtGetParentWidget() const { return GetHandle(); }
+
+
     QWidget *m_qtWindow;
 
 private:

src/qt/frame.cpp

@@ -187,11 +187,16 @@ void wxFrame::SetWindowStyleFlag( long style )
     GetQMainWindow()->setWindowFlags(qtFlags);
 }
 
+QWidget* wxFrame::QtGetParentWidget() const
+{
+    return GetQMainWindow()->centralWidget();
+}
+
 void wxFrame::AddChild( wxWindowBase *child )
 {
     // Make sure all children are children of the central widget:
 
-    QtReparent( child->GetHandle(), GetQMainWindow()->centralWidget() );
+    QtReparent( child->GetHandle(), QtGetParentWidget() );
 
     wxFrameBase::AddChild( child );
 }

src/qt/window.cpp

@@ -437,7 +437,7 @@ bool wxWindowQt::Reparent( wxWindowBase *parent )
     if ( !wxWindowBase::Reparent( parent ))
         return false;
 
-    QtReparent( GetHandle(), parent->GetHandle() );
+    QtReparent( GetHandle(), static_cast<wxWindow*>(parent)->QtGetParentWidget() );
 
     return true;
 }