[Bug 53153] New: SetWindowPos() incorrectly computes exposure region of parent window with WS_EX_COMPOSITED

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=53153

Bug ID: 53153
           Summary: SetWindowPos() incorrectly computes exposure region of
                    parent window with WS_EX_COMPOSITED
           Product: Wine
           Version: 7.10
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: wineserver
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

If a window is composited (i.e. has WS_EX_COMPOSITED set and is not using
parent DC) and repaint is triggered by calling SetWindowPos() on its child
window, the parent window's exposed region shall be the union of the old and
new visible region, *not* the difference.

Affected applications:

- KakaoTalk banner ad window is not re-painted correctly on ad rollover,
causing text artifacts from remains of the previous ad.