Oh Thunderbird...
So, I finally noticed this feature where you can open a message in a separate tab. It's probably been there for years, but I guess it only just now occurred to me that it could be useful.
So I open a message in a tab to respond to it later, and then file it where it belongs.
...and the tab then shows the next message in my in-box, instead of the one I opened. >.<
@woozle This sounds bug worthy! Please consider adding one.
Thunderbird is transitioning from being a Mozilla product to a community owned and run project by the #ThunderbirdCouncil and would become a better open source product with input like this. https://bugzilla.mozilla.org/enter_bug.cgi?format=guided#h=dupes|Thunderbird|