Bug 140542 label can't be displayed without resource file or unmatched key
Steps to reproduce: 1.New a report, add a lable with text "aaa" 2.Add a resource file for the report, set key to "key1", value to "actuate", apply the value to the label 3.Clear the resource file in Property Editor->General->Resource File (or change the key to "abc") 4.Preview the report Expected result: 1.Display label text "aaa" on preview or 2.Give a warning message to say resource file is not found or unmatched key Actual result: Nothing displays on preview
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/Module.java
*/
	public boolean removeDisposeListener( IDisposeListener listener )
	{
		if ( disposeListeners == null )
			return false;
		return disposeListeners.remove( listener );
	}
	/**
	 * Broadcasts the dispose event to the dispose listeners.
	 * 
	 * @param event
	 *            the dispose event
	 */
	public void broadcastDisposeEvent( DisposeEvent event )
	{
		if ( disposeListeners == null || disposeListeners.isEmpty( ) )
			return;
		List temp = new ArrayList( disposeListeners );
		Iterator iter = temp.iterator( );
		while ( iter.hasNext( ) )
		{
			IDisposeListener listener = (IDisposeListener) iter.next( );
			listener.moduleDisposed( (ModuleHandle) getHandle( this ), event );
		}
	}
	/**
	 * Return a list of user-defined message keys. The list contained resource
	 * keys defined in the report itself and the keys defined in the referenced
	 * message files for the current thread's locale. The list returned contains
	 * no duplicate keys.