I have installed and activated the spell check plugin. However, the misspellings get not updated automatically on modifying one's text. For example, if I type a misspelled word, it does not get marked with the red curly underline. The only way to get it marked is to switch the language, e.g. back and forth, or simply by clicking Tools -> Spell Check -> Default (en_GB) (assuming writing in English). Al new misspellings get only marked if I switch the spell check language again.