Here's a video that shows what's happening.
https://i.sstatic.net/XTAIj.jpg
It's highlighting each UI item one by one over and over.
I tried restarting my computer but it does not fix it. My computer is unusable in this state because it blocks me if I try to select something.
How do i fix this problem?
Looks like you've got something resting on your keyboard and holding down the TAB key.
