VII. Buttons that changed the world forever
The first slideshow featured two very interesting screenshots. One shows the map of Tamriel with all larger cities and the other one shows the map of Morrowind.
The map featured one more button than the retail version. Its use isn't known, but we know what it created:
When looking on the map of tamriel, you might notice that the city Daggerfall is located at the iliac bay instead of the ocean outside. On the ingame province map the city is outside. But why? It's very easy to understand when you imagine the fourth button. It would have covered the entire city making it unclickable. So the position of Daggerfall was changed. The correct location at the Iliac bay was used in TES II, but for the Oblivion codex maps, they used the wrong position.
The fourth button moved one more city and changed the landmass a bit. In Blackmarsh, the city Soulrest would have been covered like Daggerfall, so it was moved a bit to the north. When the Codex maps for oblivion were created, they looked at the Arena province maps and since the cape next to Soulrest was covered by the button the artist improvised and made it smaller because he couldn't see how far it should reach into the ocean.