Spark DataGrid rendererIsEditable

I am trying to use an item renderer as an editor. Here is my renderer code.
<?xml version="1.0" encoding="utf-8"?>
<s:GridItemRenderer xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx"
xmlns:gridEditorClasses="spark.components.gridEditorClasses.*"

<fx:Script>
<![CDATA[
import spark.events.TextOperationEvent;
override public function set data(value:Object):void

super.data = value;
if (data)

Comment.text = data[column.dataField];

protected function commentChange(event:TextOperationEvent):void

data[column.dataField] = event.target.text;

]]>
</fx:Script>
<!--- The renderer's visual component. -->
<s:VGroup width="100%" gap="0" id="mainGroup">
<s:RichEditableText id="Comment" verticalAlign="top" paddingTop="10"
paddingBottom="10" width="100%" change="commentChange(event)"
fontSize="{column.grid.dataGrid.getStyle('fontSize')}" paddingLeft="10"
selectionHighlighting="whenFocused"/>
</s:VGroup>
</s:GridItemRenderer>

What's happening is that as soon as I enter one character the editing
session is over and I need to click on the cell again to start editing
process.

Thanks