Open a Web Form, HTML, ASP, JS, VBS, CS, VB, CPP or CSS file and click Tools | Spell Checker. Spell check may take 10-15 seconds on decently sized files. There is no immediate progress indication, but you can see that squiggles appear one by one under misspelled words. Double click on the misspelled word brings list of suggestions. <Cancel> closes the suggestion list. Spell checker messages also show up in the Error List as informational messages. They are not entered as errors or warnings so they don't break builds.