Thanks for this great module! I've been digging through the code and came across something I thought was a bit strange. In multistep_form_alter(), the validation errors are limited to the current children, instead I expected #access to be set to false on the excluded children. The downside is that validation is run on all items in the form even though any errors are just ignored.

I'm sure there is a good explanation, I'd just be interested to know!