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
* <li>The {@link #userProperties}member holds the user-defined property
 * definitions for this element.</li>
 * </ul>
 * <p>
 * See also the meta-data section above for the methods that validate property
 * values, and the property value section below for methods that work with
 * property values.
 * 
 * <h3>Property Values</h3>
 * 
 * See the {@link ElementPropertyDefn}class for a description of the details of
 * property values. Property values are of two key types: normal and intrinsic.
 * Normal properties are stored in the {@link #propValues}member on this class.
 * Intrinsic properties are stored in member variables.
 * <p>
 * Normal properties have two states: <em>set</em> and <em>unset</em>. A
 * property is set on element E if a value for that property appears in the
 * propValues list for element E; otherwise it is unset on element E.
 * <p>
 * Elements inherit property values from their parent elements. So, if property
 * P is unset on element E, E will inherit the value of P from its parent
 * element.
 * <p>
 * The <em>local value</em> of a property for an element E indicates whether
 * or not the property is set on that specific element. The local value is
 * generally of interest only to low-level code. The XML design file shows only
 * the local property values for an element.
 * <p>
 * The <em>effective value </em> of a property provides the value computed
 * using the property search which includes the ancestor elements, styles,