Fretboard Diagrams

I am using Musescore 4 and so far it has been mostly successful. I did have an issue with saving fretboard diagrams to pallets but that seemed to be resolved by selecting the diagram, followed by ctrl/shift and then dragging the diagram to its pallet.
After closing the program for a day or two, I tried to open the same music score that I had been playing with only to find that I could not get the fretboard diagrams to save. The procedure of select/ctrl/shift/ drag did not work.
I seem to be missing something. Can anyone figure this out?
Thanks