Mstn seems to have persistent problems and lack of support for nested Cells.

It would be good to have a command to convert Ref attachments to nested Cells. Combined with MSR-I-1734 (a command to convert nested Cells to Ref attachments), this would give users to flip between the two data structures as required.

Programmers should also benefit if they can use more familiar code to access the nested Cells as Ref Attachments and convert the results back to Nested Cells when done.