Created attachment 165445 [details]
Possible solution

Do the following to reproduce the issue:

1. Make the main window small enough so that some of the toolbars with associated dropdowns are hidden. This could be in the NetBeans IDE (or any platform based application).
2. Invoke the overflow toolbar and then invoke the dropdown from one of the buttons. For example, in the IDE, invoke the dropdown for the Profile Project action.
3. Move the mouse to select an item from the menu.

If the mouse pointer moves outside the bounds of the overflow toolbar, even if it is inside the bounds of the dropdown, the toolbar will close along with the dropdown.

When there is a dropdown open, the overflow toolbar should remain open, at least when the mouse is inside the bounds of the dropdown and probably also even when outside the bounds as is typically the case for menus.

I've attached a possible solution that will keep the overflow toolbar open when a context menu invoked from one of the components in the toolbar is open.