Played with 1.4 installed for the first time today, as soon as I try to get to the Pip-Boy, my character pulls his arm up for a moment, making the Pip-Boy appear unusable, but then continues to pull sideways, making it impossible to use. As so the game is broken by the Pip-Boy being rendered inaccessible. This happens with existing or new saves or characters, full screen or windowed, without any mods installed.
I would attach the screenshot I captured if I could figure out how. It also took me forever to manage to get the terrible captcha you use to render in a usable state in Chrome, Bethesda. I would really appreciate some help before the DLC arrives, as I would like to be able to play it.