I am using a Mac with Big Sur (macOS Monterey, Version 12.7.5), and my email is POP, using Thunderbird Version 115.11.0. I first retrieve the mail header, then I click on "Download the rest of the message" if I wish to read the full message. When I click "Download the rest of the message" to see the contents of the actual message Thunderbird downloads the rest of the message, highlights the message (new) but then displays the next message in the list of messages in my inbox. The message I had wanted to read now becomes the previous message in the list in my inbox. I then have to go back and click on the message itself to see its contents. Please correct.