title: Check a radio button using ExtJS
body: <p>I may be missing something, but how do I programmatically check a radiobutton using ExtJS (v 3)?</p>
  
  <p>The following doesn't seem to always work</p>
  
  <p>var radio = Ext.get("myradiobutton");</p>
  
  <p>radio.set("checked,"");</p>
  
  <p>The radio is sometimes checked, sometimes not...</p>
  
  <p>radio.is(":checked") sometimes return true, sometimes false</p>
  
  <p>Thanks</p>