Bug 154828 Item from library contant user properties can't delete
Details: Item from library contant user properties can't delete Step: 1.New a library. 2.Add a label and add a user properites. 3.Public the library. 4.New a report design and use the library 5.Drop the label from library explorer into layout. 6.Try to delete it. Actual result: The label from library contant user properties can't be delete. Exception reuslt: The label can be delete.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/command/ContentCommand.java
{
		
		IElementDefn metaData = obj.getDefn( );
		if ( !metaData.isContainer( ) )
			return;
		int slotCount = metaData.getSlotCount( );
		for ( int slotID = 0; slotID < slotCount; slotID++ )
		{
			ContainerSlot slot = obj.getSlot( slotID );
			ContentCommand contentCmd = new ContentCommand( module, obj );
			while ( !slot.isEmpty( ) )
			{
				DesignElement content = slot.getContent( 0 );
				contentCmd.doRemove( content, slotID, false, true );
			}
		}
	}
	/**
	 * Moves an element from one slot to another at the specified position. The
	 * destination slot can be in the same element (unusual) or a different
	 * element (usual case). Use the other form of this method to move an
	 * element within the same slot.
	 * 
	 * @param content
	 *            the element to move.
	 * @param fromSlotID
	 *            the old slot location within the container item associated
	 *            with this command.
	 * @param to
	 *            the new container.