Does xml.copy() create completely detached copy?

Question

I am using the following code to add a new row to datagrid:
// somewhere in the code, one time when data initially is loaded into DG
newDocument = XML(documents.dataProvider[0]).copy();
// later
var NewDocument:XML = newDocument.copy();
NewDocument.id = 0;
NewDocument.docdescript = "";
NewDocument.link = "";
NewDocument.attached = "";
documents.dataProvider.addItem(NewDocument);
documents.scrollToIndex(documents.dataProvider.length - 1);
documents.selectedIndex = documents.dataProvider.length - 1;
documents.validateNow();
What's happening is when I add a second row both first and second become the same.
What is a problem here?
Thanks

Answer 1

I have a custom renderer in the first column:
<mx:itemRenderer>
<fx:Component>
<modulecode:linkButtonWordWrap color="blue" textAlign="left" fontSize="9"
label="{XML(outerDocument.documents.selectedItem).link.substr(10)}"
fontWeight="bold" fontStyle="italic" textDecoration="underline">                                                  
</modulecode:linkButtonWordWrap>
</fx:Component>
</mx:itemRenderer>
After I move setting for a label into set data it's not happening anymore.