[Bug 32507] New: UpdateLayeredWindow (wrongly) interprets alpha channel (TeamViewer 7)

http://bugs.winehq.org/show_bug.cgi?id=32507

Bug #: 32507
           Summary: UpdateLayeredWindow (wrongly) interprets alpha channel
                    (TeamViewer 7)
           Product: Wine
           Version: unspecified
          Platform: x86
               URL: http://www.teamviewer.com/en/download/linux.aspx
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: user32
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]
    Classification: Unclassified

Created attachment 42886
  --> http://bugs.winehq.org/attachment.cgi?id=42886
Screenshot of wrongly rendered overlay window

TeamViewer 7, shipped with Wine 1.21, occasionally shows some Overlay windows,
for example if somebody adds you to his contact list. (Notification will
re-appear on every login if there are unread messages)

With Wine 1.2.1, the behavior is, that it looks ugly because color keying is
not supported.

When using Wine 1.5.19, the window is totally invisible. I think the reason is
that Wine (wrongly in that case?) uses the 4th byte of the Bitmap/DC of the
window and interprets it as an alpha value, but the window is not supposed to
have per-pixel alpha.

In TeamViewer 8, shipped with Wine 1.5.19, this does not happen because the
alpha channel is explicitly set opaque, but this seems not to be necessary in
Windows.

Also, another error becomes now apparent: color keying is now supported, but
not during the alpha-fade-in and fade-out of the window. While MSDN suggests
that ULW_COLORKEY and ULW_ALPHA can not be or'ed, this works well on Windows.