designer: inform widgetset that designer handles WM_CONTEXTPOPUP message itself by Zeljan (issue #0015409)

git-svn-id: trunk@23234 -

designer/designer.pp

@@ -1571,6 +1571,7 @@ begin
     PopupPos := Point(Left + Width, Top);
   with Form.ClientToScreen(PopupPos) do
     FDesignerPopupMenu.Popup(X, Y);
+  Message.Result := 1;
 end;
 
 procedure TDesigner.GetMouseMsgShift(TheMessage: TLMMouse;