David, you are (and Mark was) a genius. I implemented your suggestion and it worked like a charm! I had always started the slur with the note I was targeting - never one to the left.
I had tried to use the arrow keys on slurs long ago, and as it moves the entire slur, I rejected it as not suiting my purpose at that time - and never went back. It certainly does the trick in this case. And, I usually ++++ to make the measures bigger, for more ease in manipulation.
Now I wish I had grumped about this long ago - you certainly would have saved me a lot of frustration!
Many thanks!
Ralph