The same problem for me. Started to occur maybe several days ago (or simply I noticed it several days ago). I don't remember such a problem occured a month or two ago, because I would have for sure noticed it.
I don't know if it is bug or not, but it is rather annoying.
My environment is:
1.05.15909 (09.07.2013 8:24), skipjack (50438), zz1, en_US, WIN 11,7,700,225, Windows 7, Chrome/27.0.1453.116, 1366x673