title: Define class in Dojo
body: <p>I'm trying to define the following class but it's giving me an error: </p>
  
  <p><strong>Error: declare dashboardFloatingPane: mixin #0 is not a callable constructor.</strong></p>
  
  <pre><code>define(["dojo/_base/declare", "dojo/dnd/move", "dojox/layout/FloatingPane"],
    function(declare, move, FloatingPane){
      return declare("dashboardFloatingPane", [move, FloatingPane], {
  
      constructor: function() {
              this.inherited(arguments);
              this.moveable = new dojo.dnd.move.constrainedMoveable(
                  this.domNode, {
                      handle: this.focusNode,
                      constraints: function() {
                          var coordsWindow = {
                              l: 0,
                              t: 20,
                              w: window.innerWidth,
                              h: window.innerHeight                            
                          };
                          return coordsWindow;
                      }, within: true
                  }
              );                            
          } 
      });
  });
  </code></pre>
  
  <p>What am I missing? </p>
  
  <p>Many thanks</p>