I think Dorico should be able to copy and paste ‘agnostically’.
In other words, if I have two instruments, say, Piccolo and Flute, it would be very helpful to be able to copy and paste both into the two staves of a piano.
At the minute, this doesn’t seem to work. When using Sibelius, this seems to work without issue - I often make quick reductions in this manner and I think it would be good if Dorico could do it without too much fuss.
You can Paste Special > Reduce to make a reduction of as many staves as you’ve selected. And Dorico is pretty smart about things like voicings and stems.
From Dorico’s point of view, what you’re doing is copying from two separate instruments and trying to paste into only one. If you had another instrument below the piano, the flute line would go in that instrument. Otherwise it is discarded, so it looks as if it doesn’t work.
Of course this can be done one staff at a time. I wonder whether this interface issue could be handled at the same time as letting pedal lines attach to the lower staff, etc.?