{
wxMenuItem *pMenuItem = (wxMenuItem *)(pMeasureStruct->itemData);
- wxCHECK_MSG( pMenuItem && pMenuItem->IsKindOf(CLASSINFO(wxMenuItem)),
+ // according to Carsten Fuchs the pointer may be NULL under XP if an
+ // MDI child frame is initially maximized, see this for more info:
+ // http://article.gmane.org/gmane.comp.lib.wxwidgets.general/27745
+ //
+ // so silently ignore it instead of asserting
+ if ( !pMenuItem )
+ return false;
+
+ wxCHECK_MSG( wxDynamicCast(pMenuItem, wxMenuItem),
false, _T("MSWOnMeasureItem: bad wxMenuItem pointer") );
size_t w, h;