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
* @param module
	 *            the module
	 * @param prop
	 *            definition of the property to get
	 * @return The property value, or null if no value is set.
	 */
	public Object getPropertyFromElement( Module module,
			ElementPropertyDefn prop )
	{
		Object value = null;
		value = getPropertyFromSelf( module, prop );
		if ( value != null )
			return value;
		
		if ( isInheritableProperty( prop ) )
		{
			if ( isVirtualElement( ) )
			{
				
				value = getPropertyFromVirtualParent( module, prop );
			}
			else
			{
				
				value = getPropertyFromParent( module, prop );
			}
			if ( value != null )
				return value;
		}