{only for GTK and X11 GUI} The number of pixels subtracted from the screen height when fitting the GUI window on the screen. Set this before the GUI is started, e.g., in your |gvimrc| file. When zero, the whole screen height will be used by the window. When positive, the specified number of pixel lines will be left for window decorations and other items on the screen. Set it to a negative value to allow windows taller than the screen.