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
IElementDefn elementDefn = dictionary.getElement( getElementName( ) );
		if ( StringUtil.isBlank( displayLabel ) )
		{
			displayLabel = elementDefn.getDisplayName( );
		}
		if ( StringUtil.isBlank( displayLabel ) )
		{
			displayLabel = elementDefn.getName( );
		}
		return displayLabel;
	}
	/**
	 * Returns the name of this element for display label.
	 * 
	 * @return the name of this element for display label.
	 */
	protected String getNameForDisplayLabel( )
	{
		return getName( );
	}
	/**
	 * All descriptive text should be "elided" to a length of 30 characters. To
	 * elide the text, find the first white-space before the limit, truncate the
	 * string after that point, and append three dots "...".
	 * <p>
	 * 
	 * @param displayLabel
	 *            the display label to be elided.
	 * @return the elided display label.
	 */