RequiredAttribute added by OdinAttributeProcessor is not considered by validation.

[nick martel]

My goal is to make everything required by default and invert the behavior with a new OptionalAttribute.

[Tor Esa Vestergaard]

This is an unfortunate but necessary consequence of decoupling validation from the drawing/property system. We will likely have to add some equivalent to attribute processors to the validation system, to support a similar feature.