Bug 315366 "Auto" for Curve Fitting Line is not black but transparent
Description: "Auto" for Curve Fitting Line is not black but transparent. Build number: 2.6.0.v20100602-0949 Steps to reproduce: 1. New a chart, in Format Chart->Series->Value (Y) Series, tick "Shown Curve Fitting Line", click "Curve Fitting Line" button. 2. Select "Auto" for Color. Expected result: The line is shown with color black. Actual result: The line disappears. Error log: N/A
chart/org.eclipse.birt.chart.ui.extension/src/org/eclipse/birt/chart/ui/swt/series/DifferenceSeriesAttributeComposite.java
btnPalette.setText( Messages.getString( "DifferenceSeriesAttributeComposite.Lbl.LinePalette" ) ); 
			btnPalette.setSelection( ( (LineSeries) series ).isPaletteLineColor( ) );
			btnPalette.addSelectionListener( this );
		}
		btnCurve = new Button( cmpButton, SWT.CHECK );
		{
			btnCurve.setLayoutData( new GridData( ) );
			btnCurve.setText( Messages.getString( "DifferenceSeriesAttributeComposite.Lbl.ShowLinesAsCurves" ) ); 
			btnCurve.setSelection( ( (DifferenceSeries) series ).isCurve( ) );
			btnCurve.addSelectionListener( this );
		}
		enableLinePaletteSetting( ( (DifferenceSeries) series ).getLineAttributes( )
				.isVisible( )
				|| ( (DifferenceSeries) series ).getNegativeLineAttributes( )
						.isVisible( ) );
	}
	public Point getPreferredSize( )
	{
		return new Point( 400, 200 );
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.swt.events.SelectionListener#widgetSelected(org.eclipse.swt.events.SelectionEvent)
	 */
	public void widgetSelected( SelectionEvent e )
	{
		if ( e.getSource( ).equals( btnCurve ) )
		{
			( (DifferenceSeries) series ).setCurve( btnCurve.getSelection( ) );