     /**
      *  Starts an editor session on a selected cell in the data grid.
      * 
-     *  A <code>startItemEditorSession</code> event is dispatch before
-     *  an item editor is created. This allows a listener a change to 
-     *  dynamically set an item editor for a specified cell. 
-     * 
-     *  The event can be cancelled which will prevent the editor session
-     *  from being created.
+     *  A <code>startItemEditorSession</code> event is dispatched before
+     *  an item editor is created. This allows a listener dynamically change 
+     *  the item editor for a specified cell. 
+     * 
+     *  The event can also be cancelled with preventDefault(), to prevent the 
+     *  editor session from being created.
      * 
      *  @param rowIndex The zero-based row index of the cell to edit.
      *  @param columnIndex The zero-based column index of the cell to edit.  

            grid.layout = null;
            gridSelection.grid = null;
            grid.gridSelection = null;
            grid.gridOwner = null;            
            
            // Event Handlers
            

        
        if (instance == columnHeaderBar)
        {
            if (grid)
                columnHeaderBar.dataGrid = this;
            
            columnHeaderBar.addEventListener(GridEvent.SEPARATOR_ROLL_OVER, separator_rollOverHandler);
            columnHeaderBar.addEventListener(GridEvent.SEPARATOR_ROLL_OUT, separator_rollOutHandler);
            columnHeaderBar.addEventListener(GridEvent.SEPARATOR_MOUSE_DOWN, separator_mouseDownHandler);
            columnHeaderBar.addEventListener(GridEvent.SEPARATOR_MOUSE_DRAG, separator_mouseDragHandler);
            columnHeaderBar.addEventListener(GridEvent.SEPARATOR_MOUSE_UP, separator_mouseUpHandler);  
        }       
    }
    
    /**
