Contextual spelling

Me again, I am working my way through my book and found in 2007 version of
Word a thing called contextual spelling. Very clever, I switched to a new
document and typed the examples given in the book and it underlined red for
spelling, green for grammar and purple for the contextual. When I went back
to the document that I put my own notes in, it only underlined the spelling
and nothing else. I made sure the document was in the new format and
everything was selected in Word options. Does anyone know why it does not
show in this document.

Margaret