[AUCTeX] Command Completion

[Gal Binyamini]

Hi all,

I have a question concerning the behvavior of the completion activated by M-
tab. When I use this and the completion is not unique, it opens a new buffer 
with suggestions. When I complete the word based on one of the suggestions, or 
click one of them, the window opened for the suggestions buffer remains open. 
Sometimes the buffer itself remains open, and sometimes it closes and is 
replaced by some other open buffer.
Is this the intended behvaior? I would much rather have this behave like a "pop-
up" window which closes as soon as I'm done completing the word. Am I doing 
something wrong?

Thanks
Gal