Leonardo Waisman commented,
Got it!!! After juggling three hours with the extend/duplicate displays, alternating which one was main display, it suddenly appeared. Cannot say I have a method, though. Thanks to all.
Leonardo Waisman commented,
Already tried both methods and they didn't work
Leonardo Waisman created a post,
Running finale 214.5 on Windows 10, with two displays. After switching back and forth between these displays, the "edit system margins" window does not appear at all.