Comment 8 for bug 1916586

On a related note (just dumping information), this is wrong and confusing:
1) add English words and some words from another language e.g. German to both subject and body
2) from context menu of either body or subject line, change language
3) with "spell check as you type" enabled, observe spell check error underlining in both body and subject
4) place cursor alternately in subject and body, observe spell checking markings
5) verify language setting in subject and body

Actual result:
3) immediately after changing language, it *looks* as if the other part (body vs. subject) also changes to the same language, as underlinings flip accordingly; but when you actually click into the other part (body vs. subject)...
4) ...you'll see that the underlinings flip back to the language previously active in that part, and...
5) ...language setting of the other part (body vs. subject) is NOT updated/synchronized in the menus.

Expected result:
decide what we want:
a) subject and body = single spell check area OR
b) subject and body = separate spell check areas

if a) single area: ensure synchronizing all aspects of spell checking immediately (language changes, ignored words).
if b) separate areas: ensure keeping all spell check aspects and behaviour separate (well ignored words could still go for all areas, but language changes must be either strictly separate OR sctrictly synchronized)

Current UX is really confusing.