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
DesignElement containerObj = this;
		int slot = slotID;
		while ( containerObj != null )
		{
			ElementDefn defn = (ElementDefn) containerObj.getDefn( );
			SlotDefn slotInfo = (SlotDefn) defn.getSlot( slot );
			if ( slotInfo != null && !slotInfo.isManagedByNameSpace( ) )
				return false;
			slot = containerObj.getContainerSlot( );
			containerObj = containerObj.getContainer( );
		}
		return true;
	}
	/**
	 * Determines whether this element is managed by namespace. If this element
	 * is a pending node or the container is not managed by the namespace,
	 * return false. Otherwise true.
	 * 
	 * @return true if this element is managed by namespace, otherwise false
	 */
	public boolean isManagedByNameSpace( )
	{
		if ( getContainer( ) == null )
			return false;
		return getContainer( ).isManagedByNameSpace( getContainerSlot( ) );
	}
	/**
	 * Determines if the current element can be transformed to a template
	 * element. False will be returned if the element can not be dropped or the
	 * container of the current element can not contain the template element.