Bug 312531 Highlight works differently when run SvgInteractivityViewer.java [13]
chart/org.eclipse.birt.chart.device.svg/src/org/eclipse/birt/chart/device/svg/SVGInteractiveRenderer.java
* Set tooltip for URLRedirect action event.
	 * 
	 * @param elm
	 * @param src
	 * @param urlValue
	 * @since 2.5
	 */
	private void setTooltipForURLRedirect( Element elm, StructureSource src,
			String tooltipText )
	{
		
		if ( ( tooltipText != null )
				&& ( tooltipText.trim( ).length( ) > 0 ) )
		{
			Element title = svg_g2d.dom.createElement( "title" ); 
			title.appendChild( svg_g2d.dom.createTextNode( tooltipText ) );
			elm.appendChild( title );
			String componentId = null;
			if ( src instanceof WrappedStructureSource )
			{
				componentId = findFirstComponentId( (WrappedStructureSource) src );
			}
			elm.setAttribute( "onmouseout", "TM.remove()" ); 
			if ( componentId != null )
				elm.setAttribute( "onmousemove", "TM.show(evt," + componentId + ")" ); 
			else
				elm.setAttribute( "onmousemove", "TM.show(evt)" ); 
		}
	}