Bug#936064: gimp: Gimp crash using filling tool

[Bernhard Übelacker]

Dear Maintainer,
this backtrace is identical to that one reported in #935604.
Also the expected message appears in this report:
    ...
    "[xcb] Unknown sequence number while processing queue"
    ....

This time I found also this upstream bugs that may be related:
    https://gitlab.gnome.org/GNOME/gimp/issues/3076
    https://gitlab.gnome.org/GNOME/gimp/issues/1475

@Stephane: By any chance, had you ClipIt running at the
           time of the crash?

Kind regards,
Bernhard