In the past Balloon terminators were place on parts, not on edges of parts.
You could move a balloon terminator to a part, but than this balloon is not locked to the view.
During one of our usergroup meetings in the Netherlands one of the user pointed out that pressing Ctrl-Alt during terminator movement solves this "problem".
I have attached a small demo. showing the Alt and the Ctrl-Alt behaviour.
Great video Jan.
Why would Ctrl be required when Alt alone can do the trick.
Hope your group also likes more uses of Alt.
ALT alone detaches the terminator from the existing line so you can re-attach to another.
CTRL+ALT allows the terminator to be re-positioned but retains the attachment.