diff --git a/src/Foundation.hs b/src/Foundation.hs
index 1faa152ff..b29f42d2a 100644
--- a/src/Foundation.hs
+++ b/src/Foundation.hs
@@ -268,8 +268,10 @@ knownTags = -- should not throw exceptions, i.e. no getBy404 or requireAuthId
          Entity sid Sheet{..} <- MaybeT . getBy $ CourseSheet cid shn
          cTime <- liftIO getCurrentTime
          case subRoute of
+           SFileR SheetExercise _ -> guard $ maybe False (<= cTime) sheetVisibleFrom
            SFileR SheetHint _ -> guard $ maybe False (<= cTime) sheetHintFrom
            SFileR SheetSolution _ -> guard $ maybe False (<= cTime) sheetSolutionFrom
+           SFileR SheetMarking _ -> mzero -- only for correctors and lecturers
            SubmissionNewR -> guard $ sheetActiveFrom <= cTime && cTime <= sheetActiveTo
            _ -> guard $ maybe False (<= cTime) sheetVisibleFrom
          return Authorized