Fix for using uncreated window

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_9_0_BRANCH@60242 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/propgrid/propgrid.cpp

@@ -1034,7 +1034,7 @@ bool wxPropertyGrid::SetFont( const wxFont& font )
     ClearSelection(false);
 
     bool res = wxScrolledWindow::SetFont( font );
-    if ( res )
+    if ( res && GetParent()) // may not have been Create()ed yet
     {
         CalculateFontAndBitmapStuff( m_vspacing );
         Refresh();