I can never get it working the way I want… here’s an example where I think it should but it doesnt:
I do: add extrema, remove a non extrema point, select the segment and undo back to the pre-add-extrema path and try to paste-replace… but no dice: http://quick.as/jpz2hxyoy
You need to select exactly what you want to replace. In the case of your video, you had a non-contiguous selection of three nodes, each separated by unselected off-curves. I assume you want to replace both segments, not just the three points…?