On the User profile fields page (Site administration -> Users -> Accounts -> User profile fields), there's a select box labelled Create a new profile field - it is an autosubmit select box, i.e. it submits a form when the value in the select box changes.

Unfortunately, the default value for it is a valid option - at time of writing it defaulted to "checkbox" - and because it defaults to a valid option, that option can never be submitted (you need to trigger a change event on the select box - going from checkbox to checkbox doesn't count as a change, and you can't change to something else first without inadvertently submitting the form).

Affected browsers:

• Affected: Chrome
• Not yet tested: Firefox, Safari, IE9 - current

Workaround
With JS disabled, the select box no longer auto-submits.

Potential solution
Make the select box default to an invalid option, perhaps using get_string('choosedots').

Perhaps this should be handled on a component level so contributors don't have to explicitly think about this?