Bug 188029 Top face is missing in Area chart of 2D+ with negative values
Top face is missing in Area chart of 2D+ with negative values. Please see attached screenshot.
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/computation/withaxes/AxisSubUnit.java
* 
	 * @param dValue
	 * @return
	 */
	public final double valuePercentage( double dValue )
	{
		if ( dPositiveTotal - dNegativeTotal == 0 )
		{
			return 0;
		}
		return ( dValue * 100d ) / ( dPositiveTotal - dNegativeTotal );
	}
	public final double getLastMaxPosition( )
	{
		return dLastMaxPosition;
	}
	public final void setLastMaxPosition( double dLastMaxPosition )
	{
		this.dLastMaxPosition = dLastMaxPosition;
	}
	public final double getLastMinPosition( )
	{
		return dLastMinPosition;
	}
	public final void setLastMinPosition( double dLastMinPosition )
	{
		this.dLastMinPosition = dLastMinPosition;
	}
}