The issue is that ctrl-tab is already used for focus cycling (especially to get out of widgets using tab like text entries), see bug #388508 or http://<email address hidden>/msg02070.html or https://bugzilla.gnome.org/show_bug.cgi?id=87764
The issue is that ctrl-tab is already used for focus cycling (especially to get out of widgets using tab like text entries), see bug #388508 or http://<email address hidden> /msg02070. html or https:/ /bugzilla. gnome.org/ show_bug. cgi?id= 87764