title: Retrieve Runtime Component dimension in ExtJS
body: <p>After a component is rendered, how can I get the width and height? I tried <code>.getWidth()</code> and <code>.getHeight()</code>, but it returns the values of config properties. It seems they are just the getters of <code>width</code> and <code>height</code> config options. </p>
  
  <p>What I want is the width and height of component after its been shown or rendered. </p>