I work at home using photoshop. Occasionally I'll have a playlist of videos playing on another monitor. There's a really annoying problem though.
Every time the next video starts, the cursor focus is taken away from the other monitor where I'm working in PS. This means (in photoshop) I could be using the lasso tool and if the next video plays the lasso selection is unfinished and creates a closed loop which is unintended and I have to start my lasso selection from scratch. This means I have to be conscious of making sure the video isn't going to end while I'm making selections. Frequently I watch tutorials which can be from 3-15 minutes so this is a constant issue.
Another example would be keyboard shortcuts. I could think I'm commanding PS to do something with a keyboard shortcut but nothing happens because it isn't in focus anymore. I have bring photoshop back into focus even though it already was in focus before vlc interrupted it.
current version is 3.0.7.1 Vetinari // Windows 10 Pro 1809 17763.557
though this has been going on for awhile so I don't think any versions have to do with it nor think it's a bug.