The problem is not the iPad itself nor dropbox but your app not supporting dropbox or the "open with..." feature. Just write to the developpers of that app to have them support both of these and you'll be in heaven...
VicoPad addict!
Not entirely true. Apple have made certain things on the iPad deliberately difficult for corporate reasons, the same way flash isn't enabled. You could argue that is Adobe's fault as much as Apples but it's all the same to me, flash is still nigh impossible on the iPhone and iPad and it COULD be easily fixed.