On the registration page when the validations for profile fields fail, the page is refreshed with error messages. The problem is that then the password form is cleared even if the user has already entered an acceptable password. Is there any way to keep the password populated even if the page is refreshed after the validation fails?
The password form field is always cleared out when re-submitting the form after a validation handler reports an error.
There isn't a workaround to that, as the password form field is not using the "#default_value" property that usually other fields would use to pre-populate the fields with a value that is then edited from users. If you use the "#value" (supposing that would have any effect for the password form field) then that value would override the value entered from the users.
I realise this post is old but I had a similar frustration. You can have the password fields not clear on validation by using client side validation.