set m_isBeingDeleted to true (only) in SendDestroyEvent(); call it as early as possible during the window destruction to ensure that destroy event handlers can still access the full window object

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@58246 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/window.h

@@ -1402,7 +1402,8 @@ protected:
     void SatisfyConstraints();
 #endif // wxUSE_CONSTRAINTS
 
-    // Send the wxWindowDestroyEvent
+    // Send the wxWindowDestroyEvent if not done yet and sets m_isBeingDeleted
+    // to true
     void SendDestroyEvent();
 
     // returns the main window of composite control; this is the window