Bug 313297 XML data set fail in chart data preview
chart/org.eclipse.birt.chart.ui/src/org/eclipse/birt/chart/ui/swt/CustomPreviewTable.java
{
					if ( getVerticalBar( ).getSelection( ) == iLastProcessedVerticalScrollPosition )
					{
						return;
					}
					if ( e.detail == SWT.ARROW_UP || e.detail == SWT.PAGE_UP )
					{
						if ( iVScroll > 0 )
						{
							iVScroll--;
						}
					}
					else if ( e.detail == SWT.ARROW_DOWN
							|| e.detail == SWT.PAGE_DOWN )
					{
						iVScroll++;
					}
					else
					{
						iVScroll += ( sb.getSelection( ) - iLastProcessedVerticalScrollPosition );
					}
					iLastProcessedVerticalScrollPosition = sb.getSelection( );
				}
				redraw( );
			}
		}
		public void widgetDefaultSelected( SelectionEvent e )
		{
		}
	}