Comment 1 for bug 1007068

Check your updates & origin of your packages/sources.
tab bar (standard one and static notebook) are scrollable and switch the active tab.

as of today the last published package is marlin 0.1-0~841~precise1 from ppa:marlin-devs/marlin-daily
If you re using random marlin's version from random ppa i can't garantee it's behavior.