preserving layout on reboot - two screens, RPI4

[LifePart2]

I have just installed a second screen on my RPI4. I have OpenCPN in a window (not full screen as that displays on only one screen), which I have split into two screens (using Layout) and then expanded so that one split is on one screen and the other on the other.

Works great.

BUT, when I ctrl-Q and reboot, I have to stretch it all out all over again. It displays on just one screen, with the split right on one edge, barely visible, which I then have to stretch out again.

I have tried to save a Layout Template, but that does not seem to restore it either. And twice it crashed when I saved and then hit OK.

So, is there some way that I can set it up so that when I boot up I end up with the split screen nicely stretched across my two HDMI screens?

Thanks,
Noel