According to brettw, when we change a misspelled word using the spellcheck context menu, we don't fire any events. This goofs up pages which are watching the textarea for changes. An example of such a page is http://www.shacknews.com/jazz/input.html (please do not use the "post" button in the upper right corner). Typing in the upper box produces a preview in the lower box. If a user types a misspelled word and then corrects it with the context menu, the preview does not change. The preview is updated properly once the user begins typing again. I'm not sure what would be the right event to fire here.
input and change events should be fired now (as far as I have tested). Feel free to reopen if they are not.