AdvancedDataGrid editable property issue - actionscript-3

Question

I have an AdvancedDataGrid control with two columns UserName and eSigner. Which looks like:
Code for this:
<mx:AdvancedDataGrid id="UserGroupGrid" left="10" bottom="40" right="10" editable="true" height="226">
<mx:dataProvider>
<mx:GroupingCollection id="gc" source="{UserGroupList}">
<mx:Grouping>
<mx:GroupingField name="UserGroupName"/>
</mx:Grouping>
</mx:GroupingCollection>
</mx:dataProvider>
<mx:columns>
<mx:AdvancedDataGridColumn textAlign="left" headerText="UserName" dataField="UserName" editable="false"/>
<mx:AdvancedDataGridColumn width="100" dataField="eSignor" headerText="eSigner" editable="true" textAlign="center" rendererIsEditor="true" editorDataField="cbSelected" editorYOffset="30">
<mx:itemRenderer>
<mx:Component>
<mx:HBox horizontalAlign="center">
<mx:Script>
<![CDATA[
public var cbSelected:Boolean;
]]>
</mx:Script>
<mx:CheckBox id="SignorCk" width="10" selected="{data.eSignor}" enabled="true" click="cbSelected = SignorCk.selected;" visible="{data.eSignor == null ? false : true}"/>
</mx:HBox>
</mx:Component>
</mx:itemRenderer>
</mx:AdvancedDataGridColumn>
</mx:columns>
</mx:AdvancedDataGrid>
As you can see in the code I want the column UserName to be non-editable and column eSigner to be editable. When I load up the page I am running into an issue where the grouping header Accounts Payable becomes editable. This happens when I click on Accounts Payable and then click somewhere off the browser and then click back on Accounts Payable again. It looks like this:
I have tried this with less success. Since the column UserName has the editable set to false I wonder what is going on here.

Answer 1

itemEditBegin="preventEdit(event);"
The property above does the trick here. In the code posted, just add this property.
<mx:AdvancedDataGrid id="UserGroupGrid" itemEditBegin="preventEdit(event);" left="10" bottom="40" right="10" editable="true" height="226">
In the script tag add the function:
private function preventEdit(event:AdvancedDataGridEvent):void
{
if(event.itemRenderer.data.UserName == null)
event.preventDefault();
}
Whenever we focus out and focus back in, on the grouping header, this would call the preventEdit function and that would cancel the events' default behavior of editing. I think this is just a workaround, hope they've fixed all this in Flex 4.
Source: Adobe