It looks like the iPhone Duo's vertical Dock can currently only house four apps maximum. In his hands-on with the device, Marques Brownlee attempted to add a fifth app to the Dock, but was unable to do so. Apple does not mention the four-app limit in its tech documentation, but those hoping to add a fifth or sixth app to it may be out of luck. For the iPhone Duo, Apple made the Dock vertical along the right of the screen, with unused space on either end of it. It will likely take some getting used to for iPhone users – especially left-handed ones. We don't know if Apple will provide a left-handed mode for the rest of us. Related Roundup: iPhone DuoTag: MKBHDBuyer's Guide: iPhone Duo (Coming Soon)Related Forum: iPhoneThis article, "iPhone Duo's Vertical Dock Seemingly Limited to Four App Icons" first appeared on MacRumors.comDiscuss this article in our forums ...read more read less