Inbox emails open as a reply from me to me in the write format with only a send option.

When I double click on an email in my inbox, it opens as a reply email from me to me in a "write" format with the only option to "send". The yellow warning at the bottom reads: A unique identity matching the From address was not found. The message will be sent using the current field and settings for identity Vince Walker with my email address. If I instead right click on the email in my inbox and ask to open in another tab it appears correctly with correct sender and options to reply reply all etc. How do I fix this? I have rebooted Thunderbird and my computer. Vince