title: Using Polymers own behaviors in Polymer 2.x
body: <p>I am experimenting with Polymer 2.x and what I don't understand is how to use Polymers own behaviors in Polymer 2.x, <code>iron-resizable-behavior</code> as an example. </p>
  
  <p>The Polymer 2.0 upgrade guide tells us that for our own components we should work with class expression mixins. That's fine but what about Polymers own behaviors? Are they in the progress of being rewritten as mixins or will they remain unchanged? There is a <code>Polymer.mixinBehaviors</code> method that seems to allow me to use Polymer 1.x mixins. Is this the final solution or is this an intermediate step?</p>
  
  <p>To phrase it another way: are the Polymer behaviors considered <strong>Polymer 2.x</strong> although we are told to use mixins for our own components?</p>
  
  <p>Sources:</p>
  
  <p><a href="https://www.polymer-project.org/2.0/docs/upgrade#upgrading-to-class-based-elements" rel="noreferrer">https://www.polymer-project.org/2.0/docs/upgrade#upgrading-to-class-based-elements</a></p>
  
  <p><a href="https://stackoverflow.com/questions/41839198/applying-behaviors-with-js-mixins-in-polymer-2">Applying Behaviors with JS Mixins in Polymer 2</a></p>