Bug 417317 Error when running chart example SwingInteractivityViewer.java.
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/render/InteractiveRenderer.java
{
	private final Map<String, Set<ActionType>> targets = new HashMap<String, Set<ActionType>>( );
	private IUpdateNotifier iun;
	private final Map<ColorDefinition, ColorDefinition> savedColors = new HashMap<ColorDefinition, ColorDefinition>( );
	private final Map<LineAttributes, LineAttributes> savedLines = new HashMap<LineAttributes, LineAttributes>( );
	private final Map<Label, Label> savedLabels = new HashMap<Label, Label>( );
	private static final IGObjectFactory goFactory = GObjectFactory.instance( );
	/**
	 * Register a chart element with an interactive action
	 * 
	 * @param target
	 * @param type
	 */
	public boolean registerAction( StructureSource target, ActionType type )
	{
		if ( iun == null )
			return false;
		String source = getSource( target );
		Set<ActionType> set = targets.get( source );
		if ( set != null )
		{
			return set.add( type );
		}
		else
		{
			set = new HashSet<ActionType>( );
			set.add( type );
			targets.put( source, set );