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
* <p>
 * <ul>
 * <li>The {@link #setExtendsElement}method sets the parent element.</li>
 * <li>The {@link #setExtendsName}method sets the name of the parent element.
 * It is used when reading a design file, or if it is necessary to store an
 * unresolved parent name.</li>
 * <li>The {@link #getExtendsElement}method gets the parent element.</li>
 * <li>The {@link #extendsRef}member stores the reference to the parent
 * element.</li>
 * </ul>
 * 
 * <h3>User-Defined Properties</h3>
 * 
 * As noted above, the user can define user-defined properties for an element.
 * User-defined properties have many of the same attributes as system-defined
 * properties. User-defined properties work virtually the same as system-defined
 * properties, including support for localization, for a property type, for
 * validating the property value, and more.
 * <p>
 * Members and classes in the user-defined property system include:
 * <p>
 * <ul>
 * <li>The {@link #addUserPropertyDefn}method defines a user-defined property.
 * </li>
 * <li>The {@link #dropUserPropertyDefn}method removes a user-defined
 * property.</li>
 * <li>The {@link #getUserPropertyDefn}method gets the definition of a
 * user-defined property.</li>
 * <li>The {@link UserPropertyDefn}class defines a user-defined property.
 * </li>