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
* 
	 * @param module
	 *            the module
	 * @param slotId
	 *            the slot id
	 * @param defn
	 *            the definition of the element
	 * @return <code>true</code> if the slot can contain the an element,
	 *         otherwise <code>false</code>.
	 */
	public final boolean canContain( Module module, int slotId,
			IElementDefn defn )
	{
		assert defn != null;
		boolean retValue = canContainInRom( slotId, defn );
		if ( !retValue )
			return false;
		
		
		if ( isRootIncludedByModule( ) )
			return false;
		if ( !canContainTemplateElement( module, slotId, defn ) )
			return false;
		
		
		if ( isVirtualElement( ) || getExtendsName( ) != null )
			return false;
		
		DesignElement tmpContainer = this;
		while ( tmpContainer != null )