Oh, so you want changing folders (or tabs) in one side to change to the same folder in the other side... I see what you were saying now. (That isn't much like navlock in that case.)
If I wanted something like that, I still wouldn't use tabs. Instead, I'd create some toolbar buttons (maybe in a menu, or in a toolbar I could toggle on and off as needed) with a button for each folder. Each button would navigate both sides of the lister to the designated folder (and maybe force Details and Thumbnails on the two sides in case it wasn't set that way already).
(You could also do that using Styles, instead of buttons, and Styles can look like a row of tabs if you want.)