Any way to shift or add measures for a single instrument

[mbagsh55]

I recently was entering a duet and while entering the second guitar realized that I had missed out a measure near the start of the piece, so the instruments were out of sync.

Adding a measure shifts both instruments - correctly - and copy & paste overwrites existing notes.
Is there a way of adding space or measures into the middle of a piece for only a single instrument, for when I make the same mistake?

Also, it may just be me, but I have problems when adding measures to the end of a piece. I find that after adding one or two measures, the focus will shift to the start of the piece and I need to scroll back down to the end of the piece again. Anyone else seeing this, or have a workaround?

Thanks,
Marcus