title: required reactive form control is invalid while pristine
body: <p>I'm having an angular reactive form with validators (taken from the scheme, but refer to it as required). The control is invlid when the form is initiate, while it is still <strong>pristine</strong>, <strong>not touched</strong> and <strong>not dirty</strong>. 
  Is there any assumption why it happens\how to avoid it ?</p>