Why did the explorer lose the frame around the active window?

Question

Windows

Either after updating the system to version Windows 10 October 2018 Update , or the frames of the explorer windows themselves broke.
The active explorer window simply does not have a frame, and it merges with other windows that are located behind it.
Example:

Google didn't provide answers, although I did find a thread from a small-soft forum where users were complaining about a similar problem in 2016.

Answer 1

I found another person with a similar problem, he said that the problem appeared just after the Windows 10 October 2018 Update.
Therefore, I have every reason to believe that the problem is in the latest update
. So we inform the developers and wait for the fix.