Issue with frame strata on the minimap.
Not sure if this is 100% just an elv/tuk issue but I moved my minimap to the bottom left of my screen and it created a dead zone of the same height all the way across the screen to the right of it. I installed SexyMap and it fixed it, presumably because it has a low frame strata. Possible solutions might be making the option to change the frame strata, or manually lowering it. I would investigate it further myself to figure out the cause but I have very little knowledge in WoW addon programming.