Allow Farbtastic color picker to clear a color choice

[mbijon]

Currently (build 21589) the Farbtastic color picker in the Theme Customizer will let you choose a color for an unset option, or change the color of an already set option.

There is not currently a way to unset the color of an option. If supported this would allow transparency or CSS inheritance to kick in.

This is a usability deficiency, so I think we should add this functionality to the Farbtastic color picker, unless the alternative color picker in #21206 gets completed and approved.

[scribu]

We should focus on the alternative color picker: #21206

If that gets scrapped, feel free to re-open.

[jazbek]

let empty values pass through hex regex so farbtastic color pickers can be cleared in theme customizer

[jazbek]

This actually has nothing to do with farbtastic, it's a bug in the regex that validates the color code. It's not allowing empty values. If you fix the regex, then the color can be cleared. I have added a patch above.

Reopening because this bug would probably be an issue with any color picker.

[mbijon]

There's a thread in the WP-hackers list that expresses frustration with this UX deficiency: ​http://lists.automattic.com/pipermail/wp-hackers/2012-August/044211.html. Based on that & @jazbek's comment, this is more-likely a UX bug than an enhancement (sorry @scribu, I didn't classify it right the 1st time).

It may make sense to have work on this proceed too, in case #21206 doesn't complete in-time. Since Matt, mattweibe, is one of the developers of Iris & owns the main patch series, some of us can't add much more there anyway.

[mbijon]

After [22030] and [22063] for #21206, this isn't needed & no parallel work is needed. Closing.