Buttons don't do anything
Fragment of a discussion from Extension talk:Semantic Forms Inputs
PS, seemed to start working if I only have one picker on a page. I had two.
You could try to update Semantic Forms, version 2.1.1 was pretty buggy. If that does not help, please try to reproduce the bug on http://scratchpad.referata.com/wiki/Form:Project_Facts. Or open the Firefox error console (ctrl-shift-J) and see if any JavaScript errors pop up.