angularjs - $watch not firing on data change

Question

I have a watch setup against the model of a ui-select2 dropdown (from ui-bootstrap). The watch fires on load but not on data changes and I can't figure out why.

It isn't the usual problem of not $apply'ing the model change or not using the third parameter for equality comparison (at least from my code).

What do I need to do to get it to fire?

Here is a plunk demonstrating the issue.

Answer 1

Try passing true as a 3rd argument to .$watch()

$rootScope.Scope documentation

$watch(watchExpression, listener, objectEquality)

objectEquality(optional) – {boolean=} – Compare object for equality rather than for reference.