Currently 24C on the activity resource page, once you have used a stock item as a resource and it's been fulfilled, you can not add the same stock item again, but you can add a different stock item from this page. If the item hasn't reached a fulfillment state, you can edit the line with the stock number, enter a new qty and start the process to the MR from there. We should be able to keep adding stock items over and over via the resource tab.