diff --git a/CHANGES.md b/CHANGES.md
index 7d1cb27e..f6371dde 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -100,6 +100,13 @@
     `OnlyLayoutFloatBelow`; `OnlyFloat` was renamed to `OnlyScreenFloat`.  See
     the documentation for more information.
 
+    The type signature of `hiddens` was changed to accept a new `Rectangle`
+    parameter representing the bounds of the parent layout, placed after the
+    `WindowSet` parameter. Anyone defining a new instance of `SetsAmbiguous`
+    will need to update their configuration. For example, replace "`hiddens amb
+    wset mst wrs =`" either with "`hiddens amb wset _ mst wrs =`" or to make
+    use of the new parameter with "`hiddens amb wset lr mst wrs =`".
+
 ### New Modules
 
   * `XMonad.Hooks.RefocusLast`
diff --git a/XMonad/Layout/NoBorders.hs b/XMonad/Layout/NoBorders.hs
index de198d60..b7f73fa1 100644
--- a/XMonad/Layout/NoBorders.hs
+++ b/XMonad/Layout/NoBorders.hs
@@ -182,7 +182,9 @@ instance (Read p, Show p, SetsAmbiguous p) => LayoutModifier (ConfigurableBorder
 -- should not have borders drawn through 'ConfigurableBorder'
 --
 -- To add your own (though perhaps those options would better belong as an
--- aditional constructor to 'Ambiguity'), you can add the function as such:
+-- additional constructor to 'Ambiguity'), you can add the following function.
+-- Note that @lr@, the parameter representing the 'Rectangle' of the parent
+-- layout, was added to 'hiddens' in 0.14. Update your instance accordingly.
 --
 -- > data MyAmbiguity = MyAmbiguity deriving (Read, Show)
 --