[Deskbar] Bug fixes

[Raphaël Slinckx <raphael slinckx net>]

Hi !

While on the plane back from the boston summit, i fixed most of the  
deskbar bugs in bugzilla (except all the crasher/segfaults ones,  
because i don't know how to reproduce, and backtraces aren't useful  
at all;.)

So please don't duplicate the work. I will commit those in 2.16  
branch ASAP (tomorrow or after-tomorrow) and then port to head as well.

See you soon,
Raf