HilitedLine of list field lost when unlocked field selected

[David Epstein]

This seems like a problem that I’ve solved before, but I can’t recall how.  With a line hilited in a locked list-behavior-true field, I can use the mouse to select text in any of a number of unlocked fields without disturbing my list’s hilite.  But if I use the tabKey to move the insertion point or selection from one unlocked field to the next, the list hilite is lost.  How can I preserve it?

Many thanks.
David Epstein