[Bug 46875] New: Corrupt screen and bad refresh on mouse movement when running Ultima Online

https://bugs.winehq.org/show_bug.cgi?id=46875

Bug ID: 46875
           Summary: Corrupt screen and bad refresh on mouse movement when
                    running Ultima Online
           Product: Wine
           Version: 4.4
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: -unknown
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

Created attachment 63937
  --> https://bugs.winehq.org/attachment.cgi?id=63937
Ultima Online screen corruption and bad refresh only with mouse movement

I've had this bug even before wine-3.0 I think. Just today I've upgraded to
wine-4.4 on Ubuntu 18.04 (amd64, wine32) and the bug showed up after just a
couple of hours of run time.

The bug shows up randomly, sometimes after many hours of the same instance of
the game client running, but especially after having logged out one character
to make another character enter the game (this also causes the game screen to
resize from 1920x1080 to 640x480 and maybe some re-initialization that triggers
the bug).

In short, the screen goes all grey and then, moving the mouse cursor, one can
"manually refresh" only a few screen blocks at a time, with the end product
being a completely corrupt game screen (see attachments).

Does anyhone have a clue about what's going on here? Is there a simple export
DISABLE_SOMETHING_GL=1 workaround that can fix this bug?

Thanks!
Avio