Comment 8 for bug 1947434

This setting (center-new-windows) was already set to false. I have Gnome Tweaks installed and this was one of the first settings I checked. This setting can be true or false; it has no effect.

Curiously, the behavior changes if I use the "Dash to Dock" extension instead of the "Ubuntu Dock".

With "Dash to Dock", the app window remembers it's size and position better (i.e. If I move the window to the primary monitor and resize it, it opens up at the same size and place).

With "Ubuntu Dock" enabled, the window always seems to randomly open on the secondary monitor, or get resized, or straddles the two displays as previously reported. Firefox and Terminal, in particular, always open with their window straddling the two displays. If I move the app window to the primary monitor, close it and reopen it, it goes back to straddling the displays.