https://bugs.winehq.org/show_bug.cgi?id=42749
--- Comment #7 from m.g.j.janicki@gmail.com --- I patched wine-2.5, as opposed to the git code. Hopefully that's alright.
With WINEDEBUG=fixme+all, the added FIXME code produces:
fixme:wgl:glxdrv_wglSwapBuffers Waiting for target_sbc 4dfdc8.
one time. I hope that's helpful.