2 files changed, 13 insertions, 2 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index b7964fa4517..6f5469f4d55 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -8,6 +8,8 @@
         (frameset-p, frameset-version, frameset-timestamp, frameset-app)
         (frameset-name, frameset-description, frameset-properties)
         (frameset-states): Add docstring.
+        (frameset-session-filter-alist, frameset-persistent-filter-alist)
+        (frameset-filter-alist): Doc fixes.
 
 2013-08-08  Juanma Barranquero  <lekktu@gmail.com>
 
diff --git a/lisp/frameset.el b/lisp/frameset.el
index 52d01c70d64..c3fdfa52886 100644
--- a/lisp/frameset.el
+++ b/lisp/frameset.el
@@ -432,7 +432,7 @@ Properties can be set with
     (minibuffer      . frameset-filter-minibuffer)
     (top             . frameset-filter-iconified))
   "Minimum set of parameters to filter for live (on-session) framesets.
-See `frameset-filter-alist' for a full description.")
+DO NOT MODIFY.  See `frameset-filter-alist' for a full description.")
 
 ;;;###autoload
 (defvar frameset-persistent-filter-alist
@@ -458,7 +458,7 @@ See `frameset-filter-alist' for a full description.")
      (window-system      . :never))
    frameset-session-filter-alist)
   "Parameters to filter for persistent framesets.
-See `frameset-filter-alist' for a full description.")
+DO NOT MODIFY.  See `frameset-filter-alist' for a full description.")
 
 ;;;###autoload
 (defvar frameset-filter-alist frameset-persistent-filter-alist
@@ -467,6 +467,15 @@ See `frameset-filter-alist' for a full description.")
 This alist is the default value of the FILTERS argument of
 `frameset-save' and `frameset-restore' (which see).
 
+Initially, `frameset-filter-alist' is set to, and shares the value of,
+`frameset-persistent-filter-alist'.  You can override any item in
+this alist by `push'ing a new item onto it.  If, for some reason, you
+intend to modify existing values, do
+
+  (setq frameset-filter-alist (copy-tree frameset-filter-alist))
+
+before changing anything.
+
 On saving, PARAMETERS is the parameter alist of each frame processed,
 and FILTERED is the parameter alist that gets saved to the frameset.