/usr/bin/gnome-shell:11:_gdk_window_has_impl:gdk_x11_window_get_xid:shell_gtk_embed_window_created_cb:g_closure_invoke:signal_emit_unlocked_R

[errors.ubuntu.com bug bridge]

The Ubuntu Error Tracker has been receiving reports about a problem regarding gnome-shell. This problem was most recently seen with package version 3.20.3-1ubuntu1~xenial1, the problem page at https://errors.ubuntu.com/problem/3434d7489f159ba504e522fe386cf086f71fd18d contains more details, including versions of packages affected, stacktrace or traceback, and individual crash reports.
If you do not have access to the Ubuntu Error Tracker and are a software developer, you can request it at http://forms.canonical.com/reports/.