Datagrid itemRenderer - Help needed

Question

I am having trouble getting this little bit of code working.  I am trying to build an adhoc SQL generator, where the user selects the list of fields and then is able to set the WHERE criteria in a dataGrid, each row has field, criteria (ComboBox -equals, less than, etc), Low (editable), High (editable-Text or ComboBox lookup), AND/OR static ComboBox.  Some of the field selections could be regular text based fields like Name and other fields selected could be lookup fields like State.  I would like to be able to on rows that are TextInput render out a TextInput for LowValue and HighValue columns and for lookup fields render out a ComboBox with the dataProvider being set by a call to addComboData.
addComboData simply uses the myDataGrid.selectedItem.fieldname to determine which of the lookup table to use and assigns that collection to CBoxdataProvider.  Seems simple enough but I have not been able to figure it out, some modifications seem to work, but only for a single dg cell others give me a list but does not populate lowValue but kill all other renderers.  All help is appreciated.
<mx:DataGridColumn headerText="Low"  rendererIsEditor="true"  editorDataField="selectedItem" dataField="lowValue" textAlign="center">
<mx:itemRenderer>
  <mx:Component>
    <mx:HBox horizontalScrollPolicy="off" verticalScrollPolicy="off" horizontalAlign="center">
       <mx:ComboBox  initialize="outerDocument.addComboData()" dataProvider="{ outerDocument.CBoxdataProvider }" labelField="Description" textAlign="left"  visible="{data.showCombo}" />
      <mx:TextInput id="lowLabel"  visible="{!data.showCombo}" />
   </mx:HBox>
  </mx:Component>
</mx:itemRenderer>
</mx:DataGridColumn>

Answer 1

Setting the selected item is not the same as a click.  If you created the renderer correctly the style should change when you actually click on the item. (Does it?)
Or are you just trying to get the first row's background to be a different style when the datagrid first shows?  (Initialization problem or not working at all?)