Run in safe mode (hold Shift when launching TB). Any difference? If it looks right in safe mode, it's probably a broken layout or hardware acceleration setting issue.

Oh that fixed it, thank you so much. So can I continue to do this all the time or do I somehow have to fix this "broken layout or hardware acceleration setting issue," when of course I have no earthly idea what either even refers to?

It was really a pain in the neck to try to deal with.

Thank you!

Launch in safe mode again, check 'Reset toolbars & controls', 'Make changes & restart' to run in normal mode. Does it still look OK in normal mode?

It came up and looked OK. The first time it did I came here to say YES and when I went back it was back to the old hidden stuff. I did it again and it looked OK but when I did the master password (I don't know if that is the cause or not) it continues to revert to the hidden stuff.

Would it be a bad thing to just keep it in safe mode?

I appreciate your help.

The master password won't affect the display, but maybe the hardware acceleration setting (Options/General, at the bottom) needs to be changed. Try it enabled or disabled, restart TB, and see if there's any difference.

YES!! It does, unchecked, it seems to be working so far. Have shut it down since unchecking a couple of times, and received and sent email. It seems to be holding.

Thank you thank you thank you, I really appreciate this help!

)

Just wanted to add my hat-tip to sfhowes. Since a Thunderbird update a couple of days ago, I had the same problem. Un-checking hardware acceleration solved the problem. Thank you very much.