diff --git a/src/Handler/Allocation/UserForm.hs b/src/Handler/Allocation/UserForm.hs
index 8618f3458..48ca7ca7d 100644
--- a/src/Handler/Allocation/UserForm.hs
+++ b/src/Handler/Allocation/UserForm.hs
@@ -220,7 +220,7 @@ courseParticipantForm courses csrf = do
                       )
   let linesWidget = Map.intersectionWith (,) courses lines'
         & Map.elems
-        & sortBy (comparing . view $ _1 . _1)
+        & sortOn (view $ _1 . _1)
         & view (folded . _2 . _2)
   return ( forM lines' $ view _1
          , $(widgetFile "allocation/user-course-participant-form/layout")