I am currently having an issue where I press Control-Alt-Delete and press Lock Computer, but my desktop is showing through the lock screen. Normally, the screen turns blue to cover the contents of my desktop, but some strange reason, this stopped happening. At that point I can actually drag the "Computer Locked" modal window around to paint over the contents of my desktop with the lock screen background
What makes it worse is that the problem seems to be intermittent. If I restart my machine, it works normally. This seems to occur only after the machine has been on for a couple days.
Has anyone ever encountered this issue?