Bug 132645 Mouse Double Click/URL Redirect on Y series of Line Chart does not work
Decription: Add a interactivity on line chart, mouse double click/URL Redirect on Y Series, does not work. Steps to reproduce: 1.Add a line chart, bind with valid dataset. 2.In the "Format Chart" tab, add a interactivity on "Value(Y) Series", the type is "Mouse Double Click", and the action is set "URL Redirect". 3.Preview in layout, click on the Y Series, interactivity does not work.
chart/org.eclipse.birt.chart.device.extension/src/org/eclipse/birt/chart/device/image/JavaxImageIOWriter.java
* 
	 * @see org.eclipse.birt.chart.device.IImageMapEmitter#getImageMap()
	 */
	public String getImageMap( )
	{
		List saList = getShapeActions( );
		if ( saList == null || saList.size( ) == 0 )
		{
			return null;
		}
		
		StringBuffer sb = new StringBuffer( );
		for ( Iterator iter = saList.iterator( ); iter.hasNext( ); )
		{
			ShapedAction sa = (ShapedAction) iter.next( );
			userCallback( sa, sb );
			String coords = shape2polyCoords( sa.getShape( ) );
			if ( coords != null )
			{
				HTMLTag tag = new HTMLTag( "AREA" ); 
				tag.addAttribute( HTMLAttribute.SHAPE, POLY_SHAPE );
				tag.addAttribute( HTMLAttribute.COORDS, coords );
				boolean changed = false;
				changed |= processOnFocus( sa, tag );
				changed |= processOnBlur( sa, tag );
				changed |= processOnClick( sa, tag );
				changed |= processOnDoubleClick( sa, tag );
				changed |= processOnMouseOver( sa, tag );
				if ( changed )
				{