Update: the gimp does the same thing as firefox and azureus so i would say that there is a very high probabilyty that this is a GTK problem.
Edit: problem solved for some reason during the update the "gtk-qt-engines" got installed wich lead to these problemes since it conflicts with the baghiraa theme that i use i don't know how i could miss that
. Anyway i removed the packege and everything is back to normal.