Hello, I am working on this bug [1] , after some investigration it seems that this is a problem of incompatibility between python-qwt5 and python-qt4. I do not know what is the best way to solve this issue. rebuild python-qwt5-qt4 but python-qt4 should be fixed also to set the right Breaks. So I would like your opinin about this . thanks for your help Frederic [1] 729392: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=729392