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
assert PropertyType.ELEMENT_REF_TYPE == prop.getTypeCode( );
		
		ElementRefValue ref = resolveElementReference( module, prop );
		return ref.isResolved( );
	}
	/**
	 * Returns the list of elements that extend this one.
	 * 
	 * @return the list of elements. The list is always non-null.
	 */
	public List getDerived( )
	{
		if ( derived != null )
			return new ArrayList( derived );
		return new ArrayList( );
	}
	/**
	 * Returns the valid status of this element. Child elements need to
	 * overwrite this method to say in which condition they can be said valid or
	 * not.
	 * <p>
	 * for example, if a JDBCDataSource can not reach the server, then it's
	 * invalid.
	 * <p>
	 * UI needs this method to show different icon for each element in the user
	 * interface.
	 * 
	 * @return true if this element is valid, false otherwise.
	 */
	public boolean isValid( )