Apologies if this issue has been posted already.
I just ran the beta for the first time after downloadingit today. If I select windowed mode at a resolution of 1280x anything The screen is pushed to the left of the monitor so that about an inch of the game area is off-screen. Furthermore, there is no way to move the window to re-center it. Fullscreen works fine. I have a surface pro laptop connected to a 24 inch monitor that is set as my primary display.
I had the same issue, I double clicked on the white bar on top or alt+enter and my issue vanished. Not sure if would work for everyone. Also I could drag and drop the window, but the mileage may vary.
i had the same issue,
once u enter the windowed mode u can adjust the size of the window from the bottom most of the window, once u successfully adjust the size of the window the top window pane will appear and u can shift it to recenter on the screen. ive been using it for a bit already, not a problem