Bug 145144 SVG Interactivity cannot highlight gradient colors
Create any SVG Chart with gradient colors on the series palette. Add interactivity on series to highlight them on mouseover for instance (or mouse click) The highlight doesn't work. It works for plain colors only.
chart/org.eclipse.birt.chart.device.svg/src/org/eclipse/birt/chart/device/svg/SVGGraphics2D.java
if ( style == null )
			style = ""; 
		if ( paint == null )
		{
			if ( color == null )
				return;
			String alpha = alphaToString( color );
			if ( alpha != null )
				style += "fill-opacity:" + alpha + ";"; 
			element.setAttribute( "style", style + "fill:" + serializeToString( color ) + ";stroke:none;" ); 
		}
		else
		{
			if ( paint instanceof SVGGradientPaint )
				element.setAttribute( "style", style + "fill:url(#" + ( (SVGGradientPaint) paint ).getId( ) + ");stroke:none;" ); 
		}
		if (styleClass != null)
			element.setAttribute("class", styleClass); 
		if (id != null)
			element.setAttribute("id", id); 
		if (( clip != null ) && (!deferClipped))
			element.setAttribute( "clip-path", "url(#clip" + clip.hashCode( ) + ")" ); 
		
	}
	/**
	 * @returns the color definition in a string with the format: #RRGGBBAA:
	 *          RRGGBB are the color components in hexa in the range 00..FF AA
	 *          is the tranparency value in hexa in the range 00..FF ex: Solid
	 *          light gray : #777777
	 */