Just adding my 2 cents here as well. This is the single most frustrating thing I have used in Basecamp. I have converted my team to using basecamp over the last 6–8 months, and with full adoption just around the corner — this happened.
Everyone on the team is complaining about navigating projects, and how it slows them down to have to reload the home page every time. Please, make this a user’s choice option. As it is, it is a royal pain.