DavecUK Yep, I can confirm I have also noticed the issue is usually (not always - sometimes it doesn’t happen, I think) is induced when opening messages in new tabs. This is how I am used to browse forums: I go over the main list, open all the threads I want to read, each in a new tab, then go over them. I will try to avoid that here, because it doesn’t work well.
However, if that can be fixed it would be good, because I am not the only one who uses the browser like this. I saw another message from a person who said they got a code instead of a photo (can’t say in which thread, because it’s not opened in another tab, :)) - I bet it’s the same issue. When you have the issue - you can’t drag and drop a photo to the post - it doesn’t work.