This is an issue, which happens in our test runs once on a hundred runs, and could be reproducible or not reproducible, depending on which machine you launch it.

You can see it on the attached movie.

Scroll to 9 minutes 10 second.

What it does :

on a scroll pane (in the center, grey) clicks left mouse button and clicks menu "item 1" -> "sub menu"

After that robot clicks on the menuButton.

Popup doesn't appear (but must).

Here that this part of test fails (as popup didn't appear).

After that test tries to click on menuBar. And this attempt fails, because click on menu in menuBar doesn't affect, looks like it is consumed (looks like, by the popup of menuButton, which is not shown). So it appears to be that popup is, and is not. I mean, it is, but it is not shown.

This issue is more likely to be reproducible on Thinkpad T410 machine.