Or if you use a continuously-fading color in the CSS for your extension (e.g. Rainbow selection), it'll eat 100% of one core just to change the background color on some text. It's a fun extension, but when my fan spins up because I forgot to deselect before switching windows, it kinda makes it less fun.
If you're interested in working out what's going on, please respond to that github issue. I understand if you don't want to spend time on such a trivial thing. But you spent the time to write this comment, so I figured maybe you're interested :)
