Hmm, stupid question.

How do I apply feathering?

Here's what I'm doing:

1. Control click on my swamp layer which selects all my swamp shapes.
2. Goto Select -> Modify-> Feather.
3. Enter a value for example 10.
4. Click ok on the feather dialog.
5. The selections change in response to the feather value I entered.
6. Now what? How do I actually apply it.