EDIT: Closing firefox and opening it again caused it to went back to the previous, normal behaviour. I have no idea what caused the problems in the first place and what caused it to behave normally now. I keep the old question below in a hope this is help identify a possible future problems. In previous versions of firefox I was commonly opening the same website in multiple tabs. For example, I would enter http://some-forum/thread in tab 1, and I would work on a reply to some thread, and in the second tab I would open http://some-forum.thread (exactly same address) so see the rest of the thread (instead of constantly jumping to the top and back of the page). However, in a new firefox (which, BTW, is getting more and more ugly with every release) entering thevery same addres in another tab simply causes switching back to an already opened tab (even if I hit the "new tab", so I clearly indicate I want a new tab!!!). It's damn frustrating. How to change that behaviour? BTW this behaviour clearly violates principle of "don't surprise the user" and I don't know why it crept into firefox into the first place... Firefox on Linux, 57.0