Inline spellchecking - Thunderbird

From MozillaZine Knowledge Base

AusDilecce has created an extension that provides inline spell checking. In other words, if you misspell a word, it will highlight it and give you suggestion. No need to manually start the spellchecker. The extension can also autocorrect many types of ordinary mistakes and can be configured to autocorrect more. You can learn more and download it here.