 //--------------------------------------
 
 /**
+ *  Horizontal space on either side of a column separator that's considered to be 
+ *  part of the separator for the sake of mouse event dispatching.
+ * 
+ *  <p>Separators are often just one pixel wide which makes interacting with them difficult.
+ *  This value is used by <code>getSeparatorIndexAt()</code> to give separators a wider
+ *  berth, so that separator events are dispatched when the mouse is closer than 
+ *  <code>separatorMouseWidth</code> to the horizontal midpoint of a separator.</p> 
+ * 
+ *  @default 5
+ * 
+ *  @langversion 3.0
+ *  @playerversion Flash 10
+ *  @playerversion AIR 1.5
+ *  @productversion Flex 4
+*/
+[Style(name="separatorAffordance", type="Number", format="Length", inherit="no")]
+
+/**
  *  Bottom inset, in pixels, for all header renderers. 
  * 
  *  @default 0

        
        layout = new GridColumnHeaderGroupLayout();
        layout.clipAndEnableScrolling = true;
        
        overlayGroup = new Group();
        overlayGroup.layout = new LayoutBase(); // no layout
        overlay.addDisplayObject(overlayGroup);
        
        // Event handlers that dispatch GridEvents
        
        MouseEventUtil.addDownDragUpListeners(this, 

        if (event.property == "horizontalScrollPosition")
            horizontalScrollPosition = Number(event.newValue);
    }        
    
    //----------------------------------
    //  visibleSortIndicatorIndices
