I have the same issue on Windows 7 (x86)
I used to have it on Vista...until 1.0, which seemed to fix it.
But yeah, got it again on 7...it's really annoying!
Found an older topic on it whilst googling:
viewtopic.php?f=2&t=67809
Not sure why that thread died - it's exactly the same problem (and yeah while you can just click and it goes away, it shouldn't be happening in the first place!
![Smile :)](./images/smilies/icon_smile.gif)
)
Edit: I've uploaded a youtube video which shows what happens:
http://www.youtube.com/watch?v=x38ZvzWwIro