When Cantabile is in full-screen mode, the main application drop-down menus (File, Edit, etc.) do not appear when you click their respective menu headers. If I had to venture a guess, I’d guess that it’s a Z-order bug.
This is under version 4.0 build 4213 running under Windows 11 build 22631.4825.
I’m on 4214 and working fine here. Make sure you have latest video drivers.
I have the latest video drivers. I also just updated to 4214 and am still seeing the same problem.
I’ve just discovered that disabling GPU-accelerated rendering (OpenGL) makes the problem go away.
I’ve also determined that when the problem is occurring, the drop-down menus are actually dropping down, because I can successfully navigate and use them (blindly) using the cursor keys and Enter. I just can’t see them.
Thanks for reporting - I’ll check it out when I get a chance. It could be that the OpenGL drive is running the display in Full Screen exclusive mode and not allowing popup windows to appear in front. Not sure there’s much I can do about that.
Are you already creating the popup windows with the WS_EX_TOPMOST flag? If not, it might be worth a try.
FWIW I have OpenGL enabled here (and working). NVidia 4070 Super.
I have an NVIDIA GeForce RTX 3090 and am using game-ready driver version 566.36.
Yes.
It might be worth trying the WHQL version (thats what I’m running). .
Do you mean the studio version?
Both the studio and game-ready drivers are WHQL-certified these days.
Not sure that’s enough GPU for Cantabile 
Yes the “studio” or whatever they are calling the non-gamer version these days. I kind of doubt it will make any difference, but still worth a try imo, just to eliminate as a possibility if nothing else.
The 3090 is OK for 3D-Cantabile. 