title: ng-dirty not reset after user manually resets field?
body: <p>What's the reasoning behind Angular's decision to not reset an input's class from <code>ng-dirty</code> to <code>ng-pristine</code> after the user manually set a field back to its initial value?</p>
  
  <p>I want to execute my save logic only if the user actually changed some of the form's data. Is there a better way than to manually hold the initial state and check for differences on submit?</p>