GTK: avoid subsequent duplicate entries in history

src/HSFM/GUI/Gtk/Utils.hs

@@ -152,8 +152,10 @@ rawPathToItem myview tp = do
 
 -- |Makes sure the list is max 5. This is probably not very efficient
 -- but we don't care, since it's a small list anyway.
-addHistory :: a -> [a] -> [a]
-addHistory i xs
+addHistory :: Eq a => a -> [a] -> [a]
+addHistory i [] = [i]
+addHistory i xs@(x:_)
+  | i == x                 = xs
   | length xs == maxLength = i : take (maxLength - 1) xs
   | otherwise              = i : xs
   where