[Bug 27669] New: Combobox, doublebuffering is not working correctly

http://bugs.winehq.org/show_bug.cgi?id=27669

Summary: Combobox, doublebuffering is not working correctly
           Product: Wine
           Version: 1.3.23
          Platform: x86
               URL: http://netikka.net/dev/black.exe
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: minor
          Priority: P2
         Component: user32
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]

Small sample: http://netikka.net/dev/black.exe

2 comboboxes. First one is normal, second I have set doublebuffered := true;

Click arrow -> combobox turns black.

Actual problem is in larger component. It uses SetWindowPos to move it and
draws icons. Problem is this black area is showing. Doublebuffering is set,
component needs it.