When I go to the top of the document, and start the spell-checker, it returns a message that spell-checking is complete, even though spelling errors are still left in the document. I then select the whole document and run the spell-checker, and then it sometimes corrects the errors.
This is a fundamental fault that needs prompt attention. I am currently using MS Word 2010 to spell-check the documents.
Somewhat belatedly, I found that you need to click the "Document" checking option. I still think the user interface for this feature should be re-oragnised so that this is clearly spelt out for the user. In any event, the "Document" option should be made the default option, i.e. when calling up the Spell checker.