Fix css for tab menu dropdown with multiple menu rows

Case:
 ![](https://photos-1.dropbox.com/t/0/AABkETNza2Qjr0Oy08eX5UIT6xACJYgYn_xzBPAmOz0lkw/12/11190302/png/1024x768/3/1384516800/0/2/Screenshot%202013-11-15%2014.06.57.png/F6kalYkrygcDwUEXcrhq3x6YHJ-waFdDYx5aTiQ-SSA)