May I be the first to ask WHAT???
Are you talking about Path anchor points? The magnetic lasso has nothing to do with a Path. You use the Delete Anchor Point tool (funnily enough) to delete an anchor point.
Sorry, I’m just learning this and I seemed to have confused the terminology. What I am referring to is the "fastening" points.
The help file states, "To erase recently drawn segments, hold down the Delete key until you’ve erased the fastening points for the desired segment". This does not appear to work and I cannot figure out why.
OK I’m with you now.
You are trying to delete the segments WHILE you are still creating the selection right? What I mean is, it’s not a closed selection, right? While you are still using the magnetic lasso you can press delete and it will remove the last segment of selection.
Try it with the Polygonal lasso for a test. Make the first three sides of a square selection (requires four clicks) then instead of making the final side to comlete the selection just press delete on your keyboard and you will go back to only having two sides to your ‘square’ selection.