How to know is a row in table view is added
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I have a project that uses core data, where there is an array controller which holds the data of the table view (created with core data).  
I need to set editable the first column of any row added (the insertion is triggered with a button).  
I tried to implement NSTableViewDelegate where there's the method:  

    - (void) tableView:(NSTableView *)tableView didAddRowView:(NSTableRowView *)rowView forRow:

But the problem is that everytime I add a row, this method gets invoked not one time, but one time for each row, so if I have a table of 10 rows and I insert a new one, the method gets invoked 11 times.So I don't really know when a new object is added.  
How do I get around this problem?  

