symfony/symfony-docs — pull request #4253 by kshishkin (2014-09-20 12:50:08+00:00)
Title: Adder and remover sidenote

| Q | A
| ------------- | ---
| Doc fix? | yes
| New docs? | no
| Applies to | all
| Fixed tickets | none

There are cases when you only want either adder or remover, important to know both of them need to be found if any is to work.