Infopath digital signatures

I have three sections on my form. One main section, one employee section and one supervisor section. The employee section has a digital signature associated with it which is set to sign the main section. The Supervisor section has a signature too and it is set to sign the employee section. Once the employee signs the employee section, all controls in the main section become locked. I would like an employee to be able to make changes if necessary, and have to resign the section. And then, when the supervisor signs, I would like form to then be non editable, unless the supervisor first removes his signature.

This seems like this should be standard stuff but apparently InfoPath just can't seem to do this. I did notice that when you go into the signature tab for the section properties dialog, it has a check box for "when signed make controls read only". It is blue, meaning it is neither checked or unchecked. I uncheck it, hit ok and close. Reopen and it's right back to blue again and it ignores my changes.