Bug 199009 [Automation][Regression] 2D percent stacked area chart did not render properly
steps to reproduce: - use the attached report design - preview in html expected behavior: - chart was renderred properly actual behavior: - it simply did not do so please refer to the attached screen captures
chart/org.eclipse.birt.chart.ui.extension/src/org/eclipse/birt/chart/ui/swt/composites/PaletteEditorComposite.java
private int iViewY = 0, iViewHeight = 0, iVisibleCount = 0,
			iSelectedIndex = 0;
	/**
	 * The height of each color entry in the palette
	 */
	private final int iItemHeight = 30;
	/**
	 * The vertical scrollbar associated with the widget
	 */
	private final ScrollBar sb;
	/**
	 * An offscreen image used to render the palette entries using double
	 * buffering. This image is re-created when a composite resize occurs.
	 */
	private Image imgBuffer = null;
	/**
	 * Associated with the offscreen image and whose lifecycle depends on the
	 * buffered image's lifecycle
	 */
	private GC gc = null;
	/**
	 * Used to edit the color definition in-place
	 */
	private Control coEditor = null;
	/**
	 * Buttons provided to alter the contents of the palette
	 */
	private Button btnAdd, btnRemove, btnUp, btnDown;
	/**
	 *