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
* See the {@link ElementDefn}class for more information on metadata, including
 * the use of the metadata definition file.
 * <p>
 * Members and classes in the meta-data system include:
 * <p>
 * <ul>
 * <li>The {@link #getDefn}method gets the element meta-data.</li>
 * <li>The {@link #getPropertyDefn}method gets the meta-data for a system- or
 * user-defined property.</li>
 * <li>The {@link #validatePropertyValue}method validates a property value
 * using the rules defined in the meta-data for the * property.</li>
 * <li>The {@link ElementDefn}class provides the meta-data for an element
 * type.</li>
 * <li>The {@link ElementPropertyDefn}class provides meta-data for a property.
 * It has two subclasses:
 * {@link org.eclipse.birt.report.model.metadata.SystemPropertyDefn}for
 * built-in properties defined in the meta-data file, and
 * {@link UserPropertyDefn}for user-defined properties.</li>
 * <li>The {@link org.eclipse.birt.report.model.metadata.MetaDataDictionary}
 * singleton class provides information to the meta-data for all elements.</li>
 * </ul>
 * 
 * <h3>Styles</h3>
 * 
 * Many elements have an associated style. Style influence the set of system-
 * defined properties, as described below. They also affect the notification
 * system as described below.
 * <p>
 * This abstract base class provides style support in the handling of property
 * values, notifications and the like. Derived classes add logic to define a