disappearing parts

I have completed a small score for beginning band. There are 14 parts. I see (and have saved) all the parts. they all appear correctly on the score, but NOT in the individual parts tabs. (where you view and print a single part.) Most of them are there, but some have disappeared. the flute tab isn't available, nor does it come up when I go to print. The percussion parts are gone too. To be clear, they DO appear on the score, but not on the individual parts tabs. Even the TABS for those parts are gone. I must have done something, because those are the first 2 parts I looked at individually. I have looked in the manuel and the blog, but haven't been able to find anything to help.