title: Clickable xaxis ticks in Flot with Categories
body: <p>I am using the categories plugin for Flot. I have the xaxis ticks. (The xaxis lists different Products.)  I want to make each xaxis tick clickable so that when you click on it, an alert is triggered with some information about that xaxis.</p>
  
  <p>however, when I add a tickFormatter function, it is completely ignored. (I have a yaxis tickformatter function that works fine.)  I think this is because of the categories plugin.</p>
  
  <p>Can anyone demonstrate the categories plugin an a tickFormatter function on the xaxis.</p>