Hi Ed, thanks very much for your help: I’ve experimented with the system monitor settings as suggested in the post to which you directed me. The problem seems to be that Avid cannot deal with a monitor arrangement where one is above the others: it can only work horizontally.
If the top monitor is primary everything works (apart from titling) but the window layout is lost on re-start. If the Left or Centre monitor is primary the layout is not lost but Avid will not allow the top monitor to be selected for Full Screen use. If the right is primary Avid’s Settings window will not open, so I can’t attempt to use my top monitor full screen.
If the Top monitor is configured as the extreme left monitor (i.e., as if it were not on top, but to the left of the existing left monitor, if you follow me) – I can use the full width of the three screens and the top monitor for full screen AND the titler works, BUT the window layout is not saved correctly.
Not ideal, because it’s counter-intuitive to move left to access an upper screen – but a useful workaround, so thank you again!