diff --git a/XMonad/Util/Grab.hs b/XMonad/Util/Grab.hs
index b1ec2074c..17073a0d0 100644
--- a/XMonad/Util/Grab.hs
+++ b/XMonad/Util/Grab.hs
@@ -29,15 +29,12 @@ module XMonad.Util.Grab
   ) where
 
 -- core
-import           XMonad                         hiding (mkGrabs)
+import           XMonad
 
 import           Control.Monad                  ( when )
-import           Data.Bits                      ( setBit )
 import           Data.Foldable                  ( traverse_ )
 -- base
-import qualified Data.Map.Strict               as M
 import           Data.Semigroup                 ( All(..) )
-import           Data.Traversable               ( for )
 
 -- }}}
 
@@ -70,9 +67,8 @@ grabUngrab
   -> [(KeyMask, KeySym)] -- ^ Keys to ungrab
   -> X ()
 grabUngrab gr ugr = do
-  f <- mkGrabs
-  traverse_ (uncurry ungrabKP) (f ugr)
-  traverse_ (uncurry grabKP)   (f gr)
+  traverse_ (uncurry ungrabKP) =<< mkGrabs ugr
+  traverse_ (uncurry grabKP)   =<< mkGrabs gr
 
 -- | A convenience function to grab keys. This also ungrabs all
 -- previously grabbed keys.
@@ -88,49 +84,9 @@ customRegrabEvHook regr = \case
   e@MappingNotifyEvent{} -> do
     io (refreshKeyboardMapping e)
     when (ev_request e `elem` [mappingKeyboard, mappingModifier])
-      $  setNumlockMask
+      $  cacheNumlockMask
       >> regr
     pure (All False)
   _ -> pure (All True)
 
 -- }}}
-
--- --< Private Utils >-- {{{
-
--- | Private action shamelessly copied and restyled from XMonad.Main source.
-setNumlockMask :: X ()
-setNumlockMask = withDisplay $ \dpy -> do
-  ms <- io (getModifierMapping dpy)
-  xs <- sequence
-    [ do
-        ks <- io (keycodeToKeysym dpy kc 0)
-        pure $ if ks == xK_Num_Lock
-          then setBit 0 (fromIntegral m)
-          else 0 :: KeyMask
-    | (m, kcs) <- ms
-    , kc       <- kcs
-    , kc /= 0
-    ]
-  modify $ \s -> s { numberlockMask = foldr (.|.) 0 xs }
-
--- | Private function shamelessly copied and refactored from XMonad.Main source.
-mkGrabs :: X ([(KeyMask, KeySym)] -> [(KeyMask, KeyCode)])
-mkGrabs = withDisplay $ \dpy -> do
-  let (minCode, maxCode) = displayKeycodes dpy
-      allCodes           = [fromIntegral minCode .. fromIntegral maxCode]
-  syms <- io . for allCodes $ \code -> keycodeToKeysym dpy code 0
-  let keysymMap = M.fromListWith (++) (zip syms $ pure <$> allCodes)
-      keysymToKeycodes sym = M.findWithDefault [] sym keysymMap
-  extraMods <- extraModifiers
-  pure $ \ks -> do
-    (mask, sym) <- ks
-    keycode     <- keysymToKeycodes sym
-    extraMod    <- extraMods
-    pure (mask .|. extraMod, keycode)
-
--- }}}
-
-
--- NOTE: there is some duplication between this module and core. The
--- latter probably will never change, but this needs to be kept in sync
--- with any potential bugs that might arise.
diff --git a/xmonad-contrib.cabal b/xmonad-contrib.cabal
index 881f8759b..edc564474 100644
--- a/xmonad-contrib.cabal
+++ b/xmonad-contrib.cabal
@@ -76,7 +76,7 @@ library
     ghc-options:   -Wall -Wno-unused-do-bind
 
     if flag(pedantic)
-       ghc-options: -Werror -Wwarn=deprecations -Wwarn=dodgy-imports
+       ghc-options: -Werror -Wwarn=deprecations
 
     -- Keep this in sync with the oldest version in 'tested-with'
     if impl(ghc > 8.6.5)
@@ -496,7 +496,7 @@ test-suite tests
   default-language: Haskell2010
 
   if flag(pedantic)
-     ghc-options: -Werror -Wwarn=deprecations -Wwarn=dodgy-imports
+     ghc-options: -Werror -Wwarn=deprecations
 
   -- Keep this in sync with the oldest version in 'tested-with'
   if impl(ghc > 8.6.5)