Editor went wrong
Copypasted piece of code from the post I'm replying to, and the editor went crazy:

The "shadow" smoothly moved with the cursor as long as it was in the editor pane. Preview showed normal text with code, but exiting preview restored the "shadow" as in the screenshot, except the "shadow" does not follow the cursor anymore.
FF102.13.0ESR, Win8.0
JW
PS. Is the ridiculously small editor pane to stay? Seriously?
