s. attached screenshot

Is already known and submitted: http://www.webyog.com/forums/index.php?showtopic=3129 (not confirmed and no info about possible fix, though)
Glad to see that I am not the only one who has those squares.

Yes, I should have used the search engine... but I was too lazy this time =)
Discussion continued in before mentioned thread.

The Issue is confirmed and It is fixed in source tree.
Please wait till next beta release.