To prevent that you can place a character like a '-' at the very left of the location bar and select the URL without that leading hyphen.

-https://support.mozilla.com/en-US/questions/760105

thanks, that does it! btw, I've noticed that typing a space after the url works, too.

You're welcome.

this was really helpful.. thank you

thank you. but why they did it like this ? there is even no about:config option! that sucks, looks ugly and deceives user (shows one thing but puts another in copy/paste buffer)... secret cheatcode instead, huh. reminds me shitty SGH-C110 phone with pile of "secret" codes you enter that can bypass all "protection" to erase all data on it, reset PINs, enable hidden features, etc.

is there bugzilla entry for that ?

hello, v-fox, I think it actually does make sense. I think that Firefox stores the address this way (percent-encoded and all.) Only when you edit the text in the address bar, does it become plain text. But, as Firefox doesn't yet know if it's an url, it doesn't know better than to copy it as-is. When you press Enter to go to that page, the text in the address bar undergoes some internal processing and becomes an address again, at which point the URL-quoting rules start to apply to it. This is how I guess how it works "under the hood." This is not to say that this behavior is indeed a bit counter-intuitive. My point is that they didn't make it like this on purpose, it just follows from how Firefox processes text in the address bar.