I notice on this particular page in Basecamp that they have two different buttons that are meant to save changes to two different sections. One section is above the fold and clearly has a "save changes" button. The second section reaches far below the fold and has a button at the bottom to "Update project access." But the first button looks like it works for both sections, especially if you don't realize there is a second button.
So, what would be a better approach for this page? If your main navigation already includes two sets of tabs, how do you break a sub-page into sections that make sense to the user?
(Assume that each section must operate separately because they use different parts of the database.)