Bug 121352 The data set binding property cannot be retrieved in report preview layout
In report preview page, the datasource/dataset property binding lists cannot be retrieved. The dataset binding can not work correctly in layout preview because it's value cannot get from the binding list. But in the data set edit page, the binding value can be got. You can refer to the attachment.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
* Inverse of the extends relationship: parent-->derived. Very few elements
	 * are extended, so we create this list only when needed.
	 */
	protected ArrayList derived = null;
	/**
	 * The unique ID assigned to this element when it is added to the design.
	 * Allows web applications to refer to the element by ID.
	 */
	protected long id = 0;
	/**
	 * Cached element definition. Cached for speed since the definition cannot
	 * change.
	 */
	protected IElementDefn cachedDefn = null;
	/**
	 * Indicates whether the element is valid. The initial value is true.
	 */
	protected boolean isValid = true;
	/**
	 * API handle for this element.
	 */
	protected DesignElementHandle handle = null;
	/**
	 * The validation error list, each of which is the instance of
	 * <code>SemanticException</code>.
	 */
	protected List errors;
	/**
	 * Constant indicate that the element has no virtual parent.
	 */