Have to click in order to get back to the active window

Hi everybody J

I’m basically forced to click after several seconds in order to continue actively in the window that I was in. Let’s say for example, right now I’m writing in this forum, and after a few seconds is like I’m automatically out of the window and I can’t write on it. I can obviously if I click on it, but then again it happens every 30 seconds or so and it’s quite annoying.

I'm on a dell XPS 13

Thanks a lot!