diff --git a/doc/emacs/custom.texi b/doc/emacs/custom.texi
index 9ba7e211013..0ffc2a0c30f 100644
--- a/doc/emacs/custom.texi
+++ b/doc/emacs/custom.texi
@@ -1417,6 +1417,8 @@ commands, and @dfn{keymaps}, which record key bindings.  It also
 explains how to customize key bindings, which is done by editing your
 init file (@pxref{Init Rebinding}).
 
+@cindex reserved key bindings
+@cindex keys, reserved
   Since most modes define their own key bindings, activating a mode
 might override your custom key bindings.  A small number of keys are
 reserved for user-defined bindings, and should not be used by modes,
diff --git a/doc/emacs/xresources.texi b/doc/emacs/xresources.texi
index 8d0127f9103..db2c6ffafd2 100644
--- a/doc/emacs/xresources.texi
+++ b/doc/emacs/xresources.texi
@@ -138,9 +138,10 @@ specifications.
 @node Table of Resources
 @appendixsec Table of X Resources for Emacs
 
-  This table lists the X resource names that Emacs recognizes,
-excluding those that control the appearance of graphical widgets like
-the menu bar:
+  The table below lists the X resource names that Emacs recognizes.
+Note that some of the resources have no effect in Emacs compiled with
+various X toolkits (GTK+, Lucid, etc.)---we indicate below when this
+is the case.
 
 @table @asis
 @item @code{background} (class @code{Background})