Since a long time ago, the input field spellchecker menu has misbehaved
but I never had enough time to report that.
language in the list of languages available. I soon notice that and
choose the right language from the menu. However, the first time I do
the change it has no effect. For some time I've thought I miss the menu
first time I change the language, but it happens every single time I do
that. On the second try, the language does indeed change, but the
changes apply very slowly; normally I need to select the whole text and
deselect it for the red underlining to disappear.

However, very soon after some time the language flips back to the first
language from the list and I have to manually change it back, twice in a
row again.

I hope this is fixed soon as I don't feel like I want to fight my
browser over orthography any more :)

src:iceweasel has been superseded by src:firefox-esr in version
45.0esr-1 in March 2016. Transitional packages to ease upgrades were
provided in the wheezy, jessie, stretch and buster releases. The
transitional packages have been removed finally before the bullseye
release in August 2021.
After regular security support for buster ended in August 2022 and LTS
support ended in June 2024, I'm closing the remaining bug reports now.

Andreas