Menu Bar doesn't adapt size when content changes

[Robin]

#12.04 LTS Precise x64
#Linux 3.2.0-37-generic

There is a menu bar for the wireless and tethered internet connections at the right upper corner of the screen.
You have disabled network connections. That's why the menu bar is very small, because there are no long network names.
You select "activate network" and the computer is searching for available networks which are now displayed in the menu bar. Therefor, the menu bar gets taller: the right end disappears, because it's too large for the screen.
The menu bar should be replaced automatically, (a few pixels to the left, in this case), when content/size changes.
Up to now, you have to close and reopen the menu bar to see the full content.

Pictures:
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