Handle "grab-broken" signal in base controller class
@brandon_lewis
Submitted by Brandon Lewis Assigned to Brandon Lewis @brandon_lewis
Description
The PiTiVi timeline behaves very poorly when a drag-and-drop grab is broken (e.g., by an error dialog). GTK+ emits a grab-broken signal, which should used by the base controller class to gracefully exit from drag modes.
Imported from https://bugzilla.gnome.org/show_bug.cgi?id=588412