Fix deleting aggregate properties from within wxPG event handler.

Do not explicitly remove sub-properties of aggregate property because they will be removed automatically in their parent property dtor.

See #16459

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77485 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/propgrid/propgridpagestate.cpp

@@ -295,7 +295,11 @@ void wxPropertyGridPageState::DoClear()
               !it.AtEnd();
               it++ )
         {
-            DoDelete(*it, true);
+            wxPGProperty *p = *it;
+            // Do not attempt to explicitly remove sub-properties.
+            // They will be removed in their parent property dtor.
+            if ( !p->GetParent()->HasFlag(wxPG_PROP_AGGREGATE) )
+                DoDelete(p, true);
         }
     }
     else