Marty, my experience with locking/unlocking is this: in plot view,
click on one of the plots so that it is "pink", click on Edit, uncheck
"Lock" by clicking it, and repeat process for the other two plots.
If they are locked one on top of another, it may be useful to go to
Text view, find one of the entries, and then go to Plot view and click
Edit, and uncheck "lock", repeating for each of the entries which need
to be unlocked. Hope this will be helpful.