Hi Martin,
Thank you for kind suggestions. I Have checked them all but my parts / tracks settings meet your criteria.
Since I was in a hurry I did this twist:
- moved majority of tracks into a folder track
- left only 4 audio tracks on cubase canvas - my problematic “VEL track” was among them
- imported “VEL track” from previously saved version of project File/Import/Tracks from project
- now a copy of “VEL track” appeared on bottom of the project
- and I could edit the imported (duplicated) audio track as all parts are completely editable and do not interfere with original track.
thank you again!