Finding out foreground app

[Taipan]

Recently I often notice that when I have my Mac sitting idle and I'm not actively using it, after a while the current foreground application (e.g. Safari) loses focus and the beachball starts spinning. I need to click into Safari's window or use cmd+< to switch back to it. The menu bar is still Safari's. So I assume that there's an application without UI getting the focus.
Is there a way to constantly display the name of the application that's currently in the foreground, so that I notice when it changes?

 

[usagora]

Found this on Google. Not sure if it works:

AppleScript/Unix: How to get the current MacOS foreground application name | alvinalexander.com

alvinalexander.com

 

[Taipan]

Found this on Google. Not sure if it works:

AppleScript/Unix: How to get the current MacOS foreground application name | alvinalexander.com

alvinalexander.com

Hm, I‘ll have to look into that. Obviously, I don’t know when the problem is going to occur, so I‘d probably have to make the script sleep for half an hour or so or get it to loop. No idea how hard that would be in AppleScript, but I‘ll check it out.
Thank you!

Edit:The script works, but it doesn't seem to catch the relevant process. It reports the app that has apparently been sent to the background.