Bug 124620 Referenced Parameter icon should be invalid if the parameter in library is deleted
Description: Referenced parameter icon should be invalid if the source parameter in library is deleted. Steps to reproduce: 1.Create a library. Insert a report scalar parameter. 2.Create a report, use the above library. In the library explorer, pull the parameter to the data explorer view of report. 3.Open the library file, delete the parameter. Then reopen the report design file, the icon of parameter seems nothing happened. But if those operations happened in dataset, the icon of dataset in the report will be invalid. It is acceptable. Expected Result: The icon of referenced parameter should be invalid.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
while ( cur.getContainer( ) != null )
		{
			DesignElement container = cur.getContainer( );
			if ( container.getExtendsElement( ) != null )
			{
				parent = container.getExtendsElement( );
				break;
			}
			cur = cur.getContainer( );
		}
		
		if ( parent == null )
			return null;
		assert parent.getContainer( ) instanceof Module;
		return parent.getRoot( ).getElementByID( baseId );
	}
	/**
	 * Gets a property value given its internal name. This version does the full
	 * property search as defined by the given derived component. That is, it
	 * gets the "effective" property value. The name can be a built-in property
	 * name or a user-defined property name. However, if the name is not valid,
	 * the method will simply return a null property value.
	 * <p>
	 * The search won't search up the inheritance hierarchy if the property is
	 * defined to not inherit.
	 * <p>
	 * Part of: Property value system.
	 * 
	 * @param module
	 *            the module