https://bugs.winehq.org/show_bug.cgi?id=53704
--- Comment #18 from Michael Stefaniuc mstefani@winehq.org --- Thanks for troubleshooting the issue.
But the proposed fix is not correct. The test was clearly showing that IDirectMusicSynth8::Open accepts a DMUS_PORTPARAMS7 on Windows. DMUS_PORTPARAMS7 is the old smaller variant of the DMUS_PORTPARAMS which is just a typedef to DMUS_PORTPARAMS8.
What happens is that BBlack passes in a DMUS_PORTPARAMS7 and your patch basically fails that function. That's why the menu entries are now disabled.
I wanted to say "Anyway IDirectMusicSynth8Impl_Open() already handles both getting a DMUS_PORTPARAMS7 as well as the full DMUS_PORTPARAMS aka DMUS_PORTPARAMS8.". But then I saw my mistake.
The fix is submitted as https://gitlab.winehq.org/wine/wine/-/merge_requests/2534