+void wxListBox::MSWOnItemsChanged()
+{
+ // we need to do two things when items change: update their max horizontal
+ // extent so that horizontal scrollbar could be shown or hidden as
+ // appropriate and also invlaidate the best size
+ //
+ // updating the max extent is slow (it's an O(N) operation) and so we defer
+ // it until the idle time but the best size should be invalidated
+ // immediately doing it in idle time is too late -- layout using incorrect
+ // old best size will have been already done by then
+
+ m_updateHorizontalExtent = true;
+
+ InvalidateBestSize();
+}
+