Is your feature request related to a problem? Please describe:

Forms often have fields that need to be inputted before submitting. We should make it possible to require fields and disable the submit button until required fields are set.

Is it possible to construct a solution with the existing API?

Yeah. Should be possible to add a Required bool field to FormItem.

Describe the solution you'd like to see:

The FormItem should have a required field and the form should then handle disabling and enabling the submit button depending on if fields have input and is validated.