Optimized update events by only sending them to visible windows

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@48854 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/window.cpp

@@ -1442,7 +1442,7 @@ void wxWindowMSW::OnInternalIdle()
     }
 #endif // !HAVE_TRACKMOUSEEVENT
 
-    if (wxUpdateUIEvent::CanUpdate(this))
+    if (wxUpdateUIEvent::CanUpdate(this) && IsShown())
         UpdateWindowUI(wxUPDATE_UI_FROMIDLE);
 }