Paste new copied notes on the window x piano roll position, not at the beggining.

Hi, I wanna know if lmms support pasting MIDI notes on the piano roll on the x position of their viewport window and not at the beggining of the piano roll track.

The issue concerns MIDI note paste behavior in the piano roll. Start by locating the piano roll's copy-and-paste handling and how its viewport x position is represented; done means pasted notes begin at the visible viewport position instead of the beginning of the track, with the existing piano roll behavior otherwise preserved.

Written by the indexing model from the issue text.