Control: found 836972 3.21.90-1 Control: tags 836972 = pending Hello Jean-Marc, Đặng Duy Sơn.
I'm happy to tell you that Michael Biebl notified me about http://bugs.debian.org/836939 which is another symptom of the same underlying issue where he had already identified the cause. The problem is a mismatch between gnome-desktop3 and mutter. Both need to be either 3.20 or 3.21/3.22. I've just committed a change that should guarantee that gnome-desktop3 3.21.x won't install together with mutter 3.20 which should resolve your issue. Hopefully mutter 3.21.x et.al. migrates to testing today, but if not then you should be able to resolve your issues by installing mutter + gnome-shell + dependencies from unstable/sid. Thanks for your feedback. Regards, Andreas Henriksson
