This is a tip for gaining access to the full tech tree when playing mods. The bug is that in a Civ 5 modded game, the tech tree loses its scroll bar, and you can't see further down the tree past the first page. To gain access to the scroll bar, simply start a new game and then get back to your game. Just follow these steps: 1) Save your game. 2) Go to the main menu, click Single Player, click Play Now - this starts a new un-modded game. 3) When the new game loads, load your modded game that you saved. When you get back into your modded game, you will have access to the full tech tree, with workable scroll bar. What I think happens is that by starting an unmodded game, the game's memory is refreshed with standard tech tree parameters which somehow stay in memory even when reloading your modded game. Exiting Civ 5 erases this memory, so that when you load Civ 5 and get back into your modded game, the tech tree bug is once again picked up. Whatever the reason why it works, all that counts is that it works. Just start a new game and reload your modded game. Only when you exit Civ 5 completely and get back in does the tech tree bug get picked up again.