[Bug 42679] New: no alpha while blitting in batches

https://bugs.winehq.org/show_bug.cgi?id=42679

Bug ID: 42679
           Summary: no alpha while blitting in batches
           Product: Wine-staging
           Version: 2.3
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: -unknown
          Assignee: [e-mail]
          Reporter: [e-mail]
                CC: [e-mail], [e-mail],
                    [e-mail]
      Distribution: ---

Created attachment 57641
  --> https://bugs.winehq.org/attachment.cgi?id=57641
fireurq2.1 - run test.qst

[I'm not the app developer, but I noticed the bug.]

The bug occurs only in staging version, Wine 2.0 stable and lower are
unaffected.
There is no alpha channel while blitting in batches, the bitmaps have black
background.

How to reproduce: see the fireurq.7z attachment;
run fireURQ2.exe, choose test.qst as the game or just run like this: wine
fireURQ2.exe test.qst

Look at the button, the letters have rough black edges on them. It shouldn't
look like that and it doesn't in Wine 2.0