Hi i have the trick solution for this problem.
1. remove the menu thing from menu widget
2. add the service "GetMenuItems" from the thing menu you created
3. map the "all data" into "menudata" of menu widget
4. trigger the GetMenuItems at the mashup loaded
Doing in this way you provide to the menu widget a dynamic dataset of data coming from the menu thing you created. It works with all broswer!