How to get value from field widget during AJAX callback loop? A select element on my form gets processed with an AJAX callback. There is a Multiselect widget on the form, and I want to see the new value of the field as if the form had been submitted. But, the $form_state['values']['my_multiselect'] is always NULL when checked in the form builder function during AJAX callback. Where does Multiselect build the value from the form state?
Looks like there's an existing answer on Multiselect issue queue: Changing multiselect options using #ajax, and it has the solution.