I am no longer able to launch my favorite image viewer, Mirage. Terminal says
"/usr/lib/python2.7/dist-packages/mirage.py:336: GtkWarning: Unable to locate theme engine in module_path: "murrine",
test = gtk.Button("", gtk.STOCK_LEAVE_FULLSCREEN)
Attempt to unlock mutex that was not locked
Similar bug report I think... the problem seems to be with Debian testing...
The mutex-bug has been solved (or worked around) for some weeks now. If you still have that problem you probably have not upgraded for some time. See http://sparkylinux.org/forum/index.php/topic,2638.0.html