Comment 7 for bug 374078

It happened to me with thunderbird.

Also when a window is maximized and you drag it out by click and push from the top to the middle of the screen, nothing happens.

And when you just click on it, the close/minimize/maximize buttons should appear but fail to do so.

Giving focus to the application (with either ALT+TAB or clicking on the window) and then moving and touching the top of the screen fails to open the application menu.