title: Angular2 component with selector not in the html
body: <p>in the following pluker <a href="http://plnkr.co/edit/MC7gO55TGkQTrxaJnJir?p=preview" rel="nofollow noreferrer">http://plnkr.co/edit/MC7gO55TGkQTrxaJnJir?p=preview</a></p>
  
  <p>in the DashboardComponent class, in the file</p>
  
  <pre><code> Dashboard.Component.ts 
  </code></pre>
  
  <p>is defined a @component with a selector but in the file .html 
  there is no selector equivalent, you can explain me how is possible?
  you are not forced to define the selector tag ?</p>