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
if ( isInheritableProperty( prop ) || prop.isStyleProperty( ) )
		{
			value = getPropertyFromParent( module, prop );
			if ( value != null )
				return value;
		}
		
		
		if ( prop.isStyleProperty( ) )
		{
			value = getPropertyFromSelfSelector( module, prop );
			if ( value != null )
				return value;
			
			
			value = getPropertyFromSlotSelector( module, prop );
			if ( value != null )
				return value;
		}
		return null;
	}
	/**
	 * Gets a property value given its definition. This version does the full
	 * property search as defined by the given derived component. That is, it
	 * gets the "effective" property value. The definition can be for a system
	 * or user-defined property.
	 * <p>
	 * The search won't search up the inheritance hierarchy if the non-style
	 * property is defined to not inherit. And style property won't be searched
	 * up the containment hierarchy if it'd defined to no inherit.