Copying unicode symbols from Firefox address bar as is

Let's say I open a webpage with some Unicode characters, say, Cyrillic, in the address like this:

http://ru.wikipedia.org/wiki/Функциональная_закреплённость

When I try to copy it from the address bar somewhere else, it becomes unreadable rubbish:

http://ru.wikipedia.org/wiki/%D0%A4%D1%83%D0%BD%D0%BA%D1%86%D0%B8%D0%BE%D0%BD%D0%B0%D0%BB%D1%8C%D0%BD%D0%B0%D1%8F_%D0%B7%D0%B0%D0%BA%D1%80%D0%B5%D0%BF%D0%BB%D1%91%D0%BD%D0%BD%D0%BE%D1%81%D1%82%D1%8C

I guess this is for compatibility. However for readability I want to copy it straight away with proper Unicode characters.

What and how should I tweak to make that possible?

Edit: The answers are good, but they are hacky. Are there any settings in about:config?