I've got both MediaLab v2012 and Inquisit 4.0. When running a MediaLab experiment, the Ctrl+Alt+right arrow doesn't lead to the end of the script, but turns the screen frame 90 degrees. I suspect this has to do with MediaLab competing with Inquisit in some way, as when I loaded Inquisit, all of the .exp files that are ML displayed an Inquisit icon. I've fixed this problem in previous versions, but can't remember how to do it.