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
*         reference a shared style.
	 */
	public StyleElement getStyle( Module module )
	{
		return null;
	}
	/**
	 * Returns the shared style referenced by this element. This method will not
	 * try to resolve the style element if the value is un-resolved.
	 * <p>
	 * Part of: Style system.
	 * 
	 * @return the shared style, or null if this element does not explicitly
	 *         reference a shared style, or the value is un-resolved
	 */
	public StyleElement getStyle( )
	{
		return null;
	}
	/**
	 * Caches an element that derives from this element.
	 * <p>
	 * Part of: Inheritance system.
	 * 
	 * @param child
	 *            The new derived element.
	 */
	protected void addDerived( DesignElement child )
	{
		if ( derived == null )