Quickform Rules

Hi. I've been playing around with the quickform class and used it to create several forms for myself. I've had some problems with the rules and was wondering if anyone could shed some light on the following things: 1) When I set a single rule for a single field to be of type "email" it seems as if that field becomes "required" too. So not filling out this field is invalid even though I want it to be optional, that it has to be a valid email or blank. Adding some rules for the _other_ input fields "email" works as expected. 2) When I submit the form and there is an error in the input all the fields are reset to blank. How do I keep fields that are valid so a user doesn't have to input all fields again ? Thanks. Birgir Stefansson