Bug 149251 Inconsistent Handling of a Non-inheritable ROM Property
For a ROM property defined to be non-inheritable, an empty string property value should be consistently handled as an empty string, not as null. For example, an oda.dataSource extension defines a data source property with canInherit=false. When a oda-data-source handle get saved in a report design, it correctly includes the tag for such property, even when an empty string value is specified. <oda-data-source extensionID="my.oda.plugin" name="my Data Source" id="24"> ... <property name="ApplicationServer"></property> </oda-data-source> However, later when using the DE API to read its property value, a null is returned. Then when the report design is subsequently saved, the property tag is lost. Expects that an empty string value of a non-inhertiable property should be preserved.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
* Checks if this element derives from the given element. The check is true
	 * if this element derives from the target, or if the target is an ancestor
	 * of this element.
	 * 
	 * @param element
	 *            The potential ancestor.
	 * @return True if the given element is an ancestor of this element, false
	 *         otherwise.
	 */
	public boolean isKindOf( DesignElement element )
	{
		DesignElement e = this;
		while ( e != null )
		{
			if ( e == element )
				return true;
			e = e.getExtendsElement( );
		}
		return false;
	}
	/**
	 * Determines if any elements extend this element.
	 * 
	 * @return True if the element is extended, false if not.
	 */
	public boolean hasDerived( )
	{
		return derived != null && derived.size( ) > 0;
	}
	/**