mark all dtors which are virtual because base class dtor is virtual explicitly virtual themselves

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@41020 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/grid.cpp

@@ -199,7 +199,7 @@ public:
                   wxGridRowLabelWindow *rowLblWin,
                   wxGridColLabelWindow *colLblWin,
                   wxWindowID id, const wxPoint &pos, const wxSize &size );
-    ~wxGridWindow() {}
+    virtual ~wxGridWindow() {}
 
     void ScrollWindow( int dx, int dy, const wxRect *rect );