I’ve been banging away at this issue today and figured it would be useful to others out there.
I made a PDF form for my company’s web site using Adobe Acrobat 8. In a couple places I have a “radio” control — that’s where you can select one, and only one, option from multiple choices. If you tick one box, all the others in that set are turned off. When distributing the blank form, however, I want all of the options to be blank. No default — the user has to pick one.
Here’s the issue: In the course of making the form, I checked one of the options, and now I can’t turn it off to distribute the form. I hunted around and got a lot of useless “you should use a checkbox instead” answers. No, I don’t need a checkbox, I just need to un-fill this field.
So how do you blank the field? You add an extra radio button to the set. Flip over to Preview, click the extra box. Back to Edit mode, delete that button. Voila! Blank radio buttons.