[Bug 57665] The Medium game launcher has no background image

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=57665

--- Comment #1 from Rémi Bernon  ---
Created attachment 77841
  --> https://bugs.winehq.org/attachment.cgi?id=77841
Fix

Thanks for the report, this should fix the issue.

The blamed change created the regression because it initializes the window
surface clipping region to a rect region matching the visible rect when it was
left empty before.

With an empty clipping region, when the window is being shown, the Expose event
we receive is ignored by `expose_window_surface`, assuming there's no redraw
necessary.

If a clipping region is set, we call NtUserRedrawWindow with RDW_ERASE which
clears the window. Somehow this application doesn't redraw its window
background in that case.