At least for me, version 9.1/Verbum.
1. Have up ESV and NA28.
2. Ensure Visual Filter/Corresponding Selection is on in both resources
3. HIghlight a word in the ESV - you'll see the corresponding word(s) highlight in NA28.
Now, go to another word(s) in the NA28, and highlight - you'll see the corresponding word highlight in the ESV, but the original word(s) in the ESV stay highlighted! It works in both directions too, it's not resource-specific from what I see.