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/StackGroup.java
{
	ArrayList alSeries = new ArrayList( );
	ArrayList alUnitPositions = null;
	final int iSharedUnitIndex;
	int iSharedUnitCount = 1;
	/**
	 * The constructor.
	 */
	StackGroup( int iSharedUnitIndex )
	{
		this.iSharedUnitIndex = iSharedUnitIndex;
	}
	/**
	 * 
	 * @param iSharedUnitCount
	 */
	final void updateCount( int iSharedUnitCount )
	{
		this.iSharedUnitCount = iSharedUnitCount;
	}
	/**
	 * 
	 * @param se
	 */