30820ab19e
A toplevel window can be unmanaged without the client knowing it (e.g. a modal dialog being unmapped together with its parent. When this has happened, take frame callbacks queued on a commit and cache them on the generic surface queue. If the toplevel is to be remapped because the surface was reassigned the toplevel role, the cached frame callbacks will be queued on the surface actor and dispatched accordingly. https://gitlab.gnome.org/GNOME/mutter/issues/240 (cherry picked from commit a740f50cd7d05582a251c23a7025999e55e4aba1)