code: function ()
  	{
  		var that = this;
  
  		var background = $('<div></div>')
  			.addClass( 'ColVis_collectionBackground' )
  			.css( 'opacity', 0 )
  			.click( function () {
  				that._fnCollectionHide.call( that, null, null );
  			} );
  
  		/* When considering a mouse over action for the activation, we also consider a mouse out
  		 * which is the same as a mouse over the background - without all the messing around of
  		 * bubbling events. Use the catcher element to avoid messing around with bubbling
  		 */
  		if ( this.s.activate == "mouseover" )
  		{
  			background.mouseover( function () {
  				that.s.overcollection = false;
  				that._fnCollectionHide.call( that, null, null );
  			} );
  		}
  
  		return background[0];
  	}
docs: Create the element used to shade the background, and capture hide events (it is shown and
  hidden as needed)
  @method  _fnDomBackground
  @returns {Node} div container for the background
  @private