Bug 156497 [Regression][Acceptance]Report isn't refreshed when delete used library file.
Description: Report isn't refreshed when delete used library file. Steps to reproduce: 1.New a library, add a label, input actuate. 2.New a report, extend lib.label 3.Delete the library file. 4.Refresh the report in Outline of the report Expected result: Empty label in Layout. Actual result: label with content "actuate" in Layout.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/command/LibraryCommand.java
*/
	private Map unresolveElementDescendent( Module module, DesignElement child )
			throws SemanticException
	{
		ElementRefValue value = (ElementRefValue) child.getLocalProperty(
				module, DesignElement.EXTENDS_PROP );
		DesignElement parent = value.getElement( );
		assert parent != null;
		
		if ( child.getDefn( ).getSlotCount( ) == 0 )
		{
			
			parent.dropDerived( child );
			value.unresolved( value.getName( ) );
			return Collections.EMPTY_MAP;
		}
		Map overriddenValues = ElementStructureUtil
				.collectPropertyValues( child );
		
		ActivityStack activityStack = getActivityStack( );
		activityStack.startSilentTrans( );
		LevelContentIterator contentIter = new LevelContentIterator( child, 1 );
		while ( contentIter.hasNext( ) )
		{
			DesignElement tmpElement = (DesignElement) contentIter.next( );
			ContentCommand command = new ContentCommand( module, child );
			command.remove( tmpElement, tmpElement.getContainerSlot( ), false,
					true );
		}
		activityStack.commit( );