~/.xmonad: Fullscreen without borders.

.xmonad/xmonad.hs

import XMonad.Hooks.DynamicLog
import XMonad.Hooks.ManageDocks (manageDocks, avoidStruts)
import XMonad.Hooks.ManageHelpers
import XMonad.Layout.NoBorders (smartBorders)
import XMonad.Layout.Fullscreen (fullscreenEventHook, fullscreenManageHook)
import XMonad.Util.Run (spawnPipe)
import XMonad.Util.EZConfig (additionalKeys)
import System.IO (hPutStrLn)
        manageHook = composeAll [
                        manageSpawn,
                        manageDocks,
                        -- Allow fullscreen
                        composeOne [ isFullscreen -?> doFullFloat ]
                        fullscreenManageHook
                     ] <+> manageHook defaultConfig,
        -- Don't overwrite the section used by docks
        layoutHook = avoidStruts $ layoutHook defaultConfig,
        handleEventHook = evHook
        layoutHook = avoidStruts $ smartBorders $ layoutHook defaultConfig,
        handleEventHook = fullscreenEventHook
     } `additionalKeys` [
        ((mod4Mask, xK_b), spawnHere "chromium --allow-file-access-from-files"),
        ((mod4Mask .|. shiftMask, xK_b), spawnHere "chromium --incognito --allow-file-access-from-files"),