I had a heck of a time isolating this from my app, so I hope you guys care =)

Steps to reproduce:
1. Run the attached sample app
2. Notice that there is a tooltip on the "Test" menu button. Notice that if you trigger the tooltip while the button menu is dropped-down, the tooltip disappears when you move the mouse over the menu items, as you would expect.
3. Click the button that says "Open stage"
4. Dismiss the popup window opened by step 3.
5. Trigger the tooltip on "Test" again. Notice that this time, the tooltip doesn't go away when you hover the mouse over the menu items. Moreover, you can trigger the tooltip to display for the first time while hovering over the menu items.

Interestingly, this problem goes away if the popup stage is not opened with APPLICATION_MODAL.