https://bugs.winehq.org/show_bug.cgi?id=39281
--- Comment #3 from Stefan Dösinger stefan@codeweavers.com --- I guess I didn't read the headers carefully enough. It uses swapeffect 4, which is D3DSWAPEFFECT_COPY_VSYNC, and I guess should be perfectly legal.
In d3d9 that's D3DSWAPEFFECT_OVERLAY, which is a d3d9ex only swapeffect...