That's unfortunately not working on firefox. There is that text area looking thingy on my screen, and it tempts me every time, and it punches me in the face every time as it copies the original URL instead of my text (on both linux, windows).

But recently I added the search bar next to the url bar for this very reason. I don't remember using it yet.

That also loses line breaks, as well as requiring significantly more steps for a single copy-paste.