title: What is different between Contextual Menu Button and Command Button in office ui fabric
body: <p>Contextual Menu Button and Command Button  looks like same in office ui fabric.what are the differences to use those button individually   ?<br>
  <a href="https://developer.microsoft.com/en-us/fabric#/controls/web/button" rel="nofollow noreferrer">Office ui fabric buttons</a></p>