Those keyboard work with any window. Not only with those of the file browser.
With GNOME Shell (with the default desktop as well?) you can make the window
take the left (respectively right) hand side of the screen with the shortcut
Meta-Left (respectively Meta-Right) where "Meta" is the windows key on most
keyboard and "Left" (respectively "Right") is the arrow pointing in that
direction. You can then open another window (with Ctrl+N for instance). If it
does not take the whole other half of the screen (here it does) then use the
related shortcut.
