This is a common problem with the update, and usually caused by a broken layout. Run in safe mode (Help/Restart with add-ons disabled). Do messages now appear in the list?

http://kb.mozillazine.org/Safe_mode#Safe_Mode_options

Thanks. Opened in safe mode with addons disabled: same problem.

In normal mode, is hardware acceleration disabled in Options(Edit/Preferences)/General, at the bottom? If it's disabled, enable it, restart TB, and see if there's any difference. Linux setups have always had unique display issues with TB, some due to the desktop theme.

Hardware accel was already checked. Doesn't help either way. Changed WM theme, just for fun: same.

Thanks.

Create a new profile from Help/Troubleshooting, about:profiles, add an account, see if it works.

That worked. Uh-oh. Does this mean re-create my original?

Thanks.

It's not as bad as you think, and faster than trying to ferret out the problem in the old profile. (I always create a new profile with major TB updates.) IMAP accounts will re-download, and local mail can be transferred by copying the mbox files in Mail/<popservername> or Mail/Local Folders to Mail/Local Folders in the new profile. Open the old profile from about:profiles, export the address books to LDIF, import them in the new profile. Install 78-compatible add-ons. Here is a partially obsolete list of other items.

thanks so much for your timely, accurate assistance.