Accept only real idle events in wxPropertyGrid::OnIdle()

Fake idle events generated e.g. by calling wxYield from within the event handler should be skipped to avoid problems.

See #16617

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78028 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/propgrid/propgrid.cpp

@@ -5783,6 +5783,11 @@ void wxPropertyGrid::OnChildKeyDown( wxKeyEvent &event )
 
 void wxPropertyGrid::OnIdle( wxIdleEvent& WXUNUSED(event) )
 {
+    // Skip fake idle events generated e.g. by calling
+    // wxYield from within event handler.
+    if ( m_processedEvent )
+        return;
+
     //
     // Check if the focus is in this control or one of its children
     wxWindow* newFocused = wxWindow::FindFocus();