Request option to copy system elements with copy/paste
There are several bugs with copy + paste.
If you select an entire piece to copy into another, none of the following things are copied:
* clef changes in a line
* rehearsal marks
If you copy several measures over the top of some existing measures that contain slurs, the slurs in the target are not removed first. So it's common to end up with multiple super-imposed slurs
Same with dynamic markings (e.g mp, ff etc) and hairpins.