MacBook Pro 16", Apple M1 Pro, MacOS Tahoe 26.4.1
When the external monitor (Dell U2715H) is set to "main", everything seems OK.
When the laptop screen is the "main" and external is extended, I get the problems. This also includes something I just tried: I can't have the notation window on my laptop with the default BIAB UI on the external. With the external monitor as main, I can have the windows on both screens. Again, this is only for notation or lead sheet. I CAN still have something like piano roll on the extra screen.
Yes, I have the displays arranged vertically with laptop on the bottom.
I just tried it with the screens arranged left-to-right and... interestingly... I can't have a floating separate notation window on one and the UI on the other, but I CAN show the notation window in the main UI (attached not floating) just fine.
And one more test, if I arrange the external monitor below the laptop screen (opposite of physical position), this works the same - OK. Not exhaustive testing, but it seems it's only when the laptop is main and arranged below the external extended monitor.
Let me know how you go smile


BIAB 2026 for Mac (started with BIAB 2006 for Windows)
Guitarist and Worship Leader from Townsville, Australia