it does not seem to support spellchecking.
Uninstalled the English language pack altogether - and there seems to be no way to reinstall it from the ADD-on tab in the browser.

Having added the Dictionary from Marco Pinto, now the spellchecking works,even without the language pack. Perhaps you explain somewhere what the language pack actually does as an add on compared to the dictionary.

Causes Waterfox to crash on launch. Need to launch Waterfox in safe-mode to uninstall the plugin and thus fix it.

Depuis la dernière MAJ de Firefox, plus aucun dictionnaire étranger ne peut s'afficher pour corriger les fautes en cours de frappe bien qu'ils soient installés. C'est un énorme bug que Firefox serait bien inspiré de réparer dans les plus brefs délais.

Perfect

very good