This has never happened before. I selected a big block of emails to delete, just like I always do. I didn't even get the change to right click and delete because every one of those emails opened. What's happened to cause this? I have Windows 10 version 2004. Here's a screenshot of the top of my Thunderbird account page so you can see what I'm talking about. I close all those and then it allowed me to delete the block. I selected another block and it did the same thing. Thank you.