alt-tab popup app switcher malfunctions if mouse pointer is over popup

When attempting to use alt-tab popup app switcher menu to change focus to an app, releasing the alt button does not close the switcher window when the mouse pointer happens to be located where the switcher popup window is.

I can get out of this by moving the mouse pointer off of the switcher window while continuing to hold down the alt key, and then when I have the mouse pointer safely off the switcher popup, then release the alt key. This is a pain that eliminates the convenience of the alt-tab switcher entirely.