Thanks for the suggestion. We had long discussions on this topic when we were first implementing the current UI back in version 10. The main reason we even have a back button is to support the scenario where a user didn't navigate to the current document from the folder browser. Maybe they received a Workflow email with a link to a document, or maybe a coworker IMed them a document link, and they want to get to the containing folder. So that's the background for why that button exists and does what it does. I agree with your premise that that functionality is not required in many scenarios, but our UI needs to support all scenarios. And while we could potentially detect which scenario best fits the user right now, we would not want to alter the UI layout or the functionality of the buttons for reasons that are not totally clear to the user.