getting the wxWindow* on GTK

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@41888 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/dcbase.cpp

@@ -1317,8 +1317,11 @@ bool wxOverlayImpl::IsOk()
 
 void wxOverlayImpl::Init( wxWindowDC* dc, int x , int y , int width , int height )
 {
+#if defined(__WXGTK__)
+    m_window = dc->m_owner;
+#else
     m_window = dc->GetWindow();
-    
+#endif
     wxMemoryDC dcMem ;
     m_bmpSaved.Create( width, height );
     dcMem.SelectObject( m_bmpSaved );