Can't click anything outside "focused/active" window

[Windows Central Question]

Hi, I have this intermittent problem where at some point during my session, I won't be able to click anything outside certain focused window. For instance, if I had task manager opened right before restarting the computer, and I couldn't click anything outside of it unless I used tab+windows key and selected another app/window. It's rather weird because it doesn't seem to happen with every application and even with applications for which it occurs, the issue isn't there after restarting my computer. It's driving me crazy, it's a brand new computer I just built and I've never experienced this issue before on my other windows computers.

 

[Ryujingt3]

What app(s) are you using when this happens? It sounds like something is taking priority and also possibly using up a lot of your hard drive, hence being frozen. Boot your PC in Safe mode, does the same thing happen?