OK, I'm having a temporary memory lapse here, and even searching my own
records, but I could swear that there is an NVDA Add-On, and I thought
it was Mozilla Apps Enhancements, that made it easy to re-order columns
under Thunderbird without the need for drag and drop.  If it is, the
documentation makes no mention of how that's done, and I have definitely
forgotten.

If anyone can shed some light, it would be appreciated.

As an aside, Thunderbird 78 includes major changes to its UI and is
still very much in beta stage.  It's completely unsurprising that
existing add-ons, whether Thunderbird's own or screen-reader based, will
not work correctly with it.  I'd expect this to remain the case until it
gets a lot closer to release and the developers of said add-ons tweak
them when release is imminent or right after it occurs.

If you are on the release channel for Thunderbird 32-bit, the latest
version is 68.10.0
--

Brian *-* Windows 10 Pro, 64-Bit, Version 1909, Build 18363  

*/Science has become just another voice in the room; it has lost its
platform.  Now, you simply declare your own truth./*

      ~ Dr. Paul A. Offit, in /New York Times/ article, /How
Anti-Vaccine Sentiment Took Hold in the United States/
<https://www.nytimes.com/2019/09/23/health/anti-vaccination-movement-us.html>/,/September
23, 2019