Implememted IsBeingDeleted() -> buttons work again

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@2405 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk1/frame.cpp

@@ -413,6 +413,8 @@ bool wxFrame::Create( wxWindow *parent, wxWindowID id, const wxString &title,
 
 wxFrame::~wxFrame()
 {
+    m_isBeingDeleted = TRUE;
+    
     if (m_frameMenuBar) delete m_frameMenuBar;
     m_frameMenuBar = (wxMenuBar *) NULL;