Hide borders for single windows

.xmonad/xmonad.hs

@@ -1,6 +1,7 @@
 import           XMonad
 import           XMonad.Hooks.DynamicLog
 import           XMonad.Hooks.ManageDocks
+import           XMonad.Layout.NoBorders      (smartBorders)
 
 import           XMonad.Layout.Magnifier
 import           XMonad.Layout.Spacing
@@ -33,7 +34,8 @@ import qualified Data.Map.Strict              as M
 import qualified XMonad.StackSet              as W
 
 -- Magnifier is off by default (can be controlled using arrow keys)
-myLayout = threeColMid |||
+myLayout = smartBorders $
+             threeColMid |||
              magnifiercz magnificationFactorH tiled |||
              magnifiercz magnificationFactorV (Mirror tiled) |||
              Full