     import org.apache.flex.html.beads.models.ArraySelectionModel;
     import org.apache.flex.html.beads.models.DataGridPresentationModel;
     import org.apache.flex.html.supportClasses.DataGridColumn;
+	import org.apache.flex.html.supportClasses.Viewport;
 	
 	/**
 	 *  The DataGridView class is the visual bead for the org.apache.flex.html.DataGrid. 

			buttonBar = new ButtonBar();
			buttonBar.addBead(buttonBarModel);
			buttonBar.addBead(bblayout);
			buttonBar.height = 25;
			buttonBar.width = UIBase(_strand).width;
			UIBase(_strand).addElement(buttonBar);

			_strand = value;
			super.strand = value;
			
			IEventDispatcher(_strand).addEventListener("sizeChanged", onSizeChanged);
			IEventDispatcher(_strand).addEventListener("widthChanged", onSizeChanged);
			IEventDispatcher(_strand).addEventListener("heightChanged", onSizeChanged);
			
			// see if there is a presentation model already in place. if not, add one.
			var modBead:IBead = _strand.getBeadByType(DataGridPresentationModel);
			var presentationModel:DataGridPresentationModel;
