Editing MIDI in PRV - MC4

OK, I'm following up on Herb's one quote from Jimmy Buffet "If we didn't all laugh we'd go insane". Yup - no where is this more necessary than in this absolutely insane hobby we have all taken up....... My latest brush with sanity occured yesterday -

Just when I thought I had MC4 and MIDI PRV editing figured out, I lost about 3 hours worth of work yesterday and I'm still not totally sure what went wrong. I figure I'll describe it here in case it happens to anyone else. So here we go:

I used Studio Instruments as a soft-synth into MC4, to bring over an el. bass part for a song I was working on. So I got a MIDI and an Audio track by default; and it plays back just fine. I worked with the MIDI file over the course of a couple days, making a lot of changes to note pitches, added more notes by copy-n-paste, etc. Standard PRV editing. At one point, I bounced that track down to a standard audio track - sounds fine. It was still incomplete, had only about half the song done and I still had a few notes a bit rough and was adjusting their duration and timing.

So yesterday I decided to go back in and try to fnish it up. I have that mixed-down audio track muted, and am working in the MIDI track in PRV edit mode. I do a few copy and pastes of some measures... continue on with editing. At one point, liking what I heard played back, I sat back and was actually pleased with it and about ready to mix it down again to audio. So, I hit W and played it back from the beginning of the song. To my dismay, I heard a bunch of garbage notes in the MIDI track near the beginning; upon close examination of the MIDI notes, I saw that numerous "pastes" of sections had duplicated themselves overtop the notes already present at those times.

I tried several times with the erasor tool, to go in and delete the excess notes and clean up the track - only to find that each time I did a Save of the project and go back and play it, the garbage was back IN the track again! Ultimately, I threw up my hands and deleted both the MIDI and synth audio tracks, keeping only the one good mixdown audio track in the project. I plan to avoid doing that kind of PRV editing again and to use direct keyboard recording instead. But, it doesn't make sense to me what happened, so I wanted to document this in case anyone else has this experience.

notes: I'm always careful during editing, to first do Select/none, then Select from here, Select until there... and then click at the left margin of the track I want, to highlight only that section. When pasting the section in, I always carefully check the correct track number and time section it gets pasted in. So I don't see how this happened; secondly, I am wondering if the track in question needs to be deselected as a "goove" track before safe editing can occur?
-John

Yeah Herb, it confirms that no one in his right mind should spend hours of editing in that mode! From here on out, I'm using live input to do at least the majority of recording, and THEN tweek just a couple notes here and there.

I don't know exactly what the box "link to original clip" means in the paste dialog, I always assumed that any changes you made to the pasted clip would also occur to the original clip. I've always unchecked that box. Maybe someone knows what it means so I don't have to do a search for it?
JD, if that ever happens again, just close the project and don't save the changes so when you open it again, at least the original track will still be there.