Once you've moved the window with the arrow keys you can also use the mouse to move the window. The problem with this is that it's _slow_, and it doesn't actually work on some software. Some non-native window frameworks like to disable (or don't implement) all hotkeys by default, including f10, Alt+space and sometimes even the tab key. IMO the only reason for a program to disable the standard windowing mechanics is because it's intended to be used as an overlay (programs like launchy or slickrun).