Can you give an example of this effect still happening? Take a screenshot and post it on imgur or imgbb, then share the link here.
This doesn't sound like it has anything to do with Windows' transparency effect in Settings. I believe it also only applies to the taskbar, Start Menu, and so-called "Modern" apps like the ones Windows comes with or you get from the Microsoft Store.When I was playing a video on youtube and then overlaid it with another app, it only showed the video, since it was mainly an audio type video
what browser?
is it still happening or fixed?
It could have just been a bad install.
I am using the nvidia drivers that come from windows update, they 2 years old but seem to work fine. I was getting bad latency using the newest ones. Depending on age of card, there comes a time the new drivers really don't help old cards.
All browsers, it happened again. Seems like its the gfx drivers causing the problem. Did the normal sfc and dism thing, didn't solve it. Re-installed the gfx drivers, and it has stopped at least for the time being
Nvidia really need to do some quality testing into their software before they release new drivers
Could have been many other causes. If the issue was related the "Nvidia's quality testing" with the version you used, I'm sure there would be a lot more instances of this across the internet. Also, when doing a reinstall of Nvidia or AMD graphics drivers, I would very highly suggest using DDU first: http://www.guru3d.com/files-details/display-driver-uninstaller-download.html
Neither company does a particularly good job with their uninstallers actually cleaning their drivers out of a system, whether you're doing a driver update, or a removal then reinstall.