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
if ( prop.isStyleProperty( ) )
		{
			value = getPropertyFromSelfSelector( module, prop );
			if ( value != null )
				return value;
			
			
			value = getPropertyFromSlotSelector( module, prop );
			if ( value != null )
				return value;
		}
		return null;
	}
	/**
	 * Gets a property value given its definition. This version does the full
	 * property search as defined by the given derived component. That is, it
	 * gets the "effective" property value. The definition can be for a system
	 * or user-defined property.
	 * <p>
	 * The search won't search up the inheritance hierarchy if the non-style
	 * property is defined to not inherit. And style property won't be searched
	 * up the containment hierarchy if it'd defined to no inherit.
	 * <p>
	 * Part of: Property value system.
	 * 
	 * @param module
	 *            the module
	 * @param prop
	 *            definition of the property to get