williamcopper
This one is easily duplicated: select a track in track view; change to PRV for a group of other tracks, not the same as selected in TV; select using the time line at the top of the PRV. You think you're getting only PRV events...
Actually, I wouldn't think that. Selecting in the Time Line, whether it's TV or PRV, selects a
region (i.e., a time range). Whatever is selected within that range
remains selected. That's the difference between selecting a
region and selecting, say, a
clip or
track.
Clicking
within the PRV grid, which is local as opposed to the global timeline, lets SONAR know you want to do something that affects only what's in the PRV. (Once you click within the PRV, SONAR de-selects tracks selected previously in the TV.) Of course all of this is influenced by how you picked tracks in the PRV (e.g., if you chose to Pick Tracks and ctrl-clicked to select multiple tracks).
Constant vigilance is needed
Understanding how SONAR does selection also works in a pinch.
Then, even when you are certain that the selection is correct, there's also the paste bug after a period of heavy editing: it basically stops working. Best solution is use 'bounce to clips' for any midi data, save and close, and re-open. If you ignore the symptoms, a crash is in your future.
It sounds like you've described the symptoms of running out of RAM. All that undo history has to be stored somewhere.