Spelling Suggestions Does Not Work Properly in Office 2007 email r

A co-worker of mine is having a strange problem. When he replies to an email
message and types a misspelled word, Outlook/Word (he is using Word as his
email editor) underlines the word but if he right clicks it for the correct
spelling suggestions it does not show them. If he composes a new message and
misspells a word the spelling suggestion feature works fine. Is this a bug?
Any help would be apprecated. Let me know if any further clarification is
needed.

Thanks.