Bug#602949: Mutter 2.29/2.31 (and metacity 2.30) doesn't recognize real screen size properly

[Mattia Tavernini]

Ok, I've found what's wrong in my configuration: I had set the
gconf-key 

/apps/metacity/general/disable_workarounds

to true. Moving it to false make cairo-dock and others applications work
correctly.