Windows 10: How to disable weird white/blue square next to apps

Hello, I installed Windows 11 and the weird white/blue squares started to show up. How can I disable them? They show if the app is selected or not but I dont like it. Pls help.

:)

 

PDF thumbnails inside of a white square

Hello Suddenly, my pdf thumbnails appear inside of a kinda white square, like this:

I have no idea why this started happening, but installing an older Adobe Reader version has not helped and I cannot undo the most recent Windows update anymore. I've tried these, but neither helped: - Clear Thumbnail Cache - Delete IconCache.db - Use this Fix - In Adobe Reader, turn off and on miniature preview Between these steps, I of couse always restarted the computer I want it to look like this:

(for some reason, I have this problem only on my laptop, but not on my desktop pc, even if both are the same Win 10 version, same updates, same Reader version, etc) Does anyone have an idea how to get rid of that? Thanks

 

Small white square on screen

I have recently noticed a small white square on the bottom right of my laptop screen. I have absolutely no idea what that is or how to take it off. Here is a print screen.





This little white square is not on the top of everything on the screen. If, say, I click on the notifications button, we do not see the square





Any idea of what that is? Or how to get rid of it?

If it is relevant, on the tray I have:

• CCleaner
  
• Acer Care Center
  
• GeForce 920M
  
• Avast
  
• NVidia GeForce Experience
  
• Avast SecureLine
  
• Drive File Stream
  

My computer is an Acer Aspire E15 with Windows 10, 64 bits.

 

Computer Acts Strange with the White Square in the Start Menu and Other Utilities.

My copy of Windows 10 is. making a weird glitch. There's this... white square which appears in the start menu, task bar, and when I plug headphones is. Depending on where it is, it auto scrolls, or outright refuses to let me press an option. I've restarted
my keyboard drivers, since the white square is tied to the tab key, I've tried SFC, nothing has worked... I don't know what to do...