Something's definitely misbehaving in Firefox on the page. Using a mouse to highlight text in a comment and then trying to move the highlight to the next paragraph, the selection jumps to the first paragraph as soon as the cursor leaves the `span` of each paragraph.

From a quick look at the DOM, I'd bet dollars to donuts it's the weird combination of custom WebComponents and the #shadow-root stuff and other various markup excess that they just didn't bother to test with Firefox. Whether it's a bug with Firefox itself and how these elements are handled, I guess would need some investigation. But if it were my web app, I'd probably just fix it instead of blaming the browser.

Screen capture: https://imgur.com/RmoSZRB

The text isn't rendering at all in Safari/Mac. (Momentarily too lazy/tired to find out why. 2am here.)

Why is a simple, factual report downvoted? Should I add a screenshot?

If you create a new Firefox profile alongside your usual one, and do not change any settings, can you reproduce the copy paste issue you’re seeing?

im also getting it after trying with troubleshooting mode on (disables extensions, themes and custom settings.) this is on windows and latest firefox 90.0.2

https://i.imgur.com/y5lkfHI.gif

Huh, TIL. I suppose I'd recommend a report to Webcompat.

Tried with a brand new Firefox profile, on OSX. Still wonky.

Screencast: https://youtu.be/XGTyDQGTC4E

Works fine in Firefox, too.

Not for me on OSX. New FF profile to rule out extensions/settings; https://youtu.be/XGTyDQGTC4E.