Sometimes the top 96 pixels of a maximized window disappear and are no longer click-able. Instead the click is received and handled by the desktop. This happens randomly on my Windows 10 Pro (10.0.16299) machine, which is a dual-monitor system as you can see. The issue is independent of the applications used; it happens in any application, but it cannot be triggered by a special action or similar. I first noticed it in Excel. Later in Firefox’s development tools and now quite often in Opera. All software is the latest. When it happens in a browser toggling full-screen on/off by pressing F11 helps sometimes. Otherwise a reboot is required to make it work again, because restarting the application does not help. Very annoying. Here’s a screenshot how it looks like:
I believe this is an error related to the display driver (Intel HD 4600, version 184.108.40.20635), but prove me wrong. In case anyone has a suggestion what might be the cause, mail me.