mhevery/angular.js — comment on commit 3a1e32dcf70a33dd06ce607922e41173d639ca09
File: docs/src/templates/doc_widgets.js line 94
By mhevery:

I adde comment explaining why.

I think you are misreading the code. We $watch one scope and delegate the $watches to another scope. The scope registration returns a de-registration function which we pass to $destroy for cleanup.