Broken Feature: Node selection across masters

It used to be that when selecting a node in a master and then going to another master the corresponding node in the other master was also selected.
In 3.1.1 (3135) this feature is not working. (And probably on previous versions but I don’t know exactly which ones).

Are the outlines compatible and have you enabled the syncing in the Edit menu?

I thought it was always on.
Now it works perfectly. Thanks.