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
* sent for each change using subclasses of the {@link NotificationEvent}class.
 * See these two classes for more details.
 * <p>
 * Note: subscribing and unsubscribing listeners is the only mutator operation
 * that the application can (and should) do without the use of a command.
 * <p>
 * Members and classes in the notification system include:
 * <p>
 * <ul>
 * <li>The {@link #listeners}member holds the list of subscribed listeners.
 * </li>
 * <li>The {@link #addListener}and {@link #removeListener}methods to add and
 * remove listeners.</li>
 * <li>The {@link Listener}class to receive notifications.</li>
 * <li>A subclass of {@link NotificationEvent}notifies the listener of the
 * type of change, and information about the change.</li>
 * <li>The {@link org.eclipse.birt.report.model.activity.ActivityStack}class
 * triggers the notifications as it processes commands.</li>
 * <li>ActivityStack calls the {@link #sendEvent}method to send the
 * notification to the appropriate listeners.</li>
 * <li>The sendEvent( ) method in turn calls
 * {@link #broadcast(NotificationEvent)}to do the detailed work of sending an
 * event to all the listeners.</li>
 * </ul>
 * 
 * <h3>Element Identity</h3>
 * 
 * There are four ways to refer to an item:
 * <p>
 * <dl>