The system of allowing/blocking remote content is too basic for practical use. The problem is that if you use it as intended you still get the remote content message that you must remove by clicking the X because tracking servers change the URL a bit, so there's always something new to block. The menu only offers to allow/trust remote content, not to block, so you must allow all then search a long list for the right items then block them after writing the entire URL by hand, then clicking Block. Without a wildcard (*) in the URL, it gets tedious to the point of being impractical and you must allow all domains from the sender (including trackers and future trackers). I don't see why it has stayed so simplistic after all this time. At the very least, we should be able to disable the remote content message if we had allowed/blocked sender already.