Bug 188283 Bubbles should be z-sorted by size in Bubble charts
Biggest bubbles should be drawn first so that there is no small bubble hidden by a bigger one.
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/render/DeferredCache.java
*/
	public final void addLine( LineRenderEvent lre )
	{
		if ( lre instanceof I3DRenderEvent )
		{
			if ( lre.getLineAttributes( ) != null
					&& lre.getLineAttributes( ).isSetVisible( )
					&& lre.getLineAttributes( ).isVisible( ) )
			{
				al3D.add( lre.copy( ) );
			}
		}
		else
		{
			alLines.add( lre.copy( ) );
		}
	}
	/**
	 * Adds text rendering event to cache.
	 */
	public final void addLabel( TextRenderEvent tre )
	{
		if ( tre instanceof I3DRenderEvent )
		{
			al3D.add( tre.copy( ) );
		}
		else
		{
			alLabels.add( tre.copy( ) );
		}