Unacceptably long alt+tab on Windows 10

I have a borderless window with the size of my monitor resolution. With the latest Windows 10 update after pressing Win key (or alt+tab), it takes about 5 seconds for task bar to pop up.

Is anyone experiencing similar behaviour?

P.S. My code used to work without this kind of delay.

I have also seen longer fullscreen switching and ALT+TAB switching from fullscreen since the Win 10 update. I haven’t had a chance to profile why this is yet.

In case it’s GPU driver related, I have an AMD R9 Nano and am on Radeon Software Version 17.7. My copy of glfw is built from master on 7 Feb 2018.

If I get a chance to look into this I’ll report back here.

I’ve tracked the problem down via a search online and confirmed it’s a new Windows 10 feature called focus assist. See here for fix:

Thanks a lot for your research. I think I didn’t notice slow downs with apps using DirectX, but I’ll have to check. Hopefully this gets fixed soon.