      *  lastName properties, or do some custom formatting on a Date value
      *  property.</p>
      *
-     * 
      *  @default null
      * 
      *  @see #itemToDataTip

    
    /**
     *  Specifies a callback function to run on each item of the data provider 
     *  to determine its dataTip.
     *  This property is used by the <code>itemToDataTip</code> method.
     * 
     *  <p>By default, if <code>showDataTips</code> is <code>true</code>,
     *  the column looks for a property named <code>label</code>
     *  on each data provider item and displays it as its dataTip.
     *  However, some data providers do not have a <code>label</code> property 
     *  nor do they have another property that you can use for displaying data 
     *  in the rows.
     *  For example, you might have a data provider that contains a lastName 
     *  and firstName fields, but you want to display full names as the dataTip.
     *  You can specify a function to the <code>dataTipFunction</code> property 
     *  that returns a single String containing the value of both fields. You 
     *  can also use the <code>dataTipFunction</code> property for handling 
     *  formatting and localization.</p>
     * 
     *  <p>The dataTipFunction's signature must match the following:
     * 
     *  <pre>dataTipFunction(item:Object, column:GridColumn):String</pre>
     *

    [Inspectable(category="General")]
    
    /**
     *  Specifies the formatter used by the column's <code>itemToDataTip()</code> method to 
     *  convert data provider items to Strings.
     * 
     *  <p>If the formatter's <code>styleParent</code> was not specified, it's set
     *  to the column's grid, so that the formatter inherits the grid's <code>locale</code> style.</p>
     *
     *  @default null
     * 
