custom powerpoint template does not catch spelling errors

I've searched this issue, and can't seem to find an answer. I'm
working with a custom template in powerpoint 2007 (and 2008 on Mac).
Unfortunately, the spell checking for misspelled words doesn't seem to
work. I can misspell a word in a blank default presentation, and the
spell check will catch that error. The same misspelled word in my
custom template does not get flagged. I've confirmed that the nasty
"Do not check spelling" checkbox is UNchecked, and the text is marked
as English (US). I'm at a loss as to what to try next. Anyone have any
ideas? I'd be glad to share the file with you, if that will help.

TIA!
Brad