I saw this coming. The developers for Thunderbird are elitist snobs, and they're not really interested in helping the common business user.
One of the simplest requests entered into their Bugzilla tracker is to create a 'reply' message with full headers, similar to the way they do their 'forward' message.
https://bugzilla.mozilla.org/show_bug.cgi?id=218258 The developers flat-out refuse to do it because "that's the way Microsoft does it". Never mind that some businesses require full traceability for compliance issues. This feature was requested 9 years ago!
Another shortcoming was its lack of support for MAPI name resolution... Thunderbird couldn't be called successfully from 3rd party programs in Windows. That issue only took 8 years to fix.
https://bugzilla.mozilla.org/show_bug.cgi?id=244222I would have loved to ditch Outlook, but until functionality existed to replace some key indispensable features, it wasn't going to happen. Now it probably never will.
