The Menu itself doesn't have this functionality, however the Popup widget that Menu uses for its submenus has a deactivate event which you can probably use. This can be difficult though, since the Menu popups are created on demand. So, to ease the task, I went ahead and created activate/deactivate events for the Menu and all wrappers. You will find them in the Q1 release due for release on 20th of March. As a workaround until then, you can use a 200ms or more setTimeout in the close event to simulate it.
Let me know if this helps.
the Telerik team
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