I want to show a hidden form element if one check fails in validation function.
This use case is user has submited sensitive data and that hidden element(a checkbox) will unhide to make sure he really wants to submit the data.
After user checks that checkbox, this validation will
pass. Pretty straightforward, but the challenge is how to make form knows this form has been validated
and failed. So it knows it needs to unhide that checkbox.
I tried adding variable in $form_state, but all elements inside $form_state will be ingored when
Any help will be appreciated. Thank you!