[Plugin: SimpleModal Login] How to remove scroll bars on forms

I would like to remove the scroll bars on the Login & registration forms.

I know that I can do this with CSS proporty overflow: hidden however I can not find the right div to put it against or where to put it.

Any assistance would be appreciated.

It is worth noting that if I enter the forms via the login link & then click on register from the login form, I do not get any scroll bars. However is I enter the register form from the main register link directly & the click login from within the register form, I get scroll bars on both forms.

Cheers.

http://wordpress.org/extend/plugins/simplemodal-login/