Spellchecker not working

[taem]

Windows 10 on a PC
64-bit processor
Thunderbird 91.5.0 (64-bit)
<NO> Extensions installed

So, sometime last week, T.Bird stopped properly spell-checking my emails as I type them. Checking online, people said to verify your dictionary is downloaded and selected, I did that. Bug remains. T.Bird will start spell-checking the first sentence or two of an email showing red squiggly lines on misspelled words, then stops after that and will not spell-check anything past that point. What the hell? It's in every single email. Rather I restart my PC or not.

Repeatable 100% of the time: Start a new email. Write text more than a couple of sentences deep with notable spelling errors. Only the top visible row will get spell-checked while the rest of the document does not.

T.Bird spell-checker was working fine before last week. I did not install anything on my PC, but I cannot be certain if T.Bird or Windows did not auto-update sometime last week... Thank's for any help ahead of time.

[James]

duplicate of http://forums.mozillazine.org/viewtopic ... &t=3085864 thread.