Make select2 optional and uncheck hidden fields

I didn't see any dependencies on select2, so I added a check for it.

I also have a requirement to reset/uncheck any checkboxes in the hidden dependent fields. I wasn't sure if this is something you would want or if there's some more customizable way to allow it, so I'm open to any suggestions.

Lastly, I can break these into 2 separate pull requests if you want.