Thunderbird corrupted panacea.dat causing slowness

I had major thunderbird slowness issues. Just scrolling the folder list (grabbing the folder list scrollbar and moving it, or moving the scrollwheel while in the list) would lead to no thunderbird screen updates for a second or two. Clicking on a mailbox did the same, clicking on messages took even longer. Some discussion on https://bugzilla.mozilla.org/show_bug.cgi?id=794401 led to me removing panacea.dat. This could have been the wrong thing to do, alta88 does say that folder pretty names might be lost. I'm on thunderbird 38.4.0 though, not the 12,13,14,15 versions discussed in the bug report. That may be why, after just removing the file, I didn't lose any pretty folder names. That certainly has sped up thunderbird so it's now usable and now I won't need to switch to evolution :-)