+ i.e. if GetEditControl() returns non-NULL. In particular, do not call
+ it from EVT_LIST_BEGIN_LABEL_EDIT handler as the edit control is not
+ yet fully created by then, just veto the event in this handler instead
+ to prevent the editing from even starting.
+
+ Notice that calling this method will result in EVT_LIST_END_LABEL_EDIT
+ event being generated.