How do I get FF to open a new window on my current screen when I press Command-N, rather than on another screen where FF already has a window open?
On the Mac, iOS 10.13.4 (High Sierra) and FireFox 59.0.2, and on every version of FF I've ever used, pressing Command-N on a screen that does not have a FF window opens the new window on a screen where FF already has another open window. The window doesn't open on the current screen.
So after pressing Cmd-N, FF has changed my screen. To get back, I have to show screens (four finger swipe up), and drag the newly opened window back to the screen where I originated Cmd-N.
It isn't terribly broken. It's just a poor user experience.
Opaite Mbohovái (2)
I didn’t investigate thoroughly nor do I use a Mac, but perhaps you could take a look at this bug and express your thoughts? Does the behavior depend on whether or not windows are maximized?
Additionally (and I don’t know how this is implemented in the Firefox code), I do know default application behavior sometimes is to open a second instance on the primary screen, i.e. regardless of any present window’s size, screen position or screen, even for corporate applications. That means you could consider switching the primary and secondary screen at hardware level as a workaround if that makes any difference.
I also found a report of an add-on called Monitor Master which is unfortunately no longer supported as of Firefox Quantum (57+). I couldn’t find another one but maybe there is one that could help.
Hope this helps a bit anyway.
Thank you Tonnes, for your response.
Because you don't use a Mac, it's hard to understand the problem. "Screen" in this context is multiple desktops on one device, not multiple display devices as in the bug that you referred to. There is however some possibility that the two are related.