diff --git a/content/completion.js b/content/completion.js
index f72dc806..a86e7d0a 100644
--- a/content/completion.js
+++ b/content/completion.js
@@ -1394,7 +1394,14 @@ function Completion() //{{{
             context.completions = completions;
         },
 
-        preference: function preference(filter) commands.get("set").completer(filter, true), // XXX
+        preference: function preference(context)
+        {
+            let prefs = Components.classes["@mozilla.org/preferences-service;1"]
+                                  .getService(Components.interfaces.nsIPrefBranch);
+            context.title = ["Firefox Preference", "Value"];
+            context.keys = { text: function (item) item.item, description: function (item) options.getPref(item.item) };
+            context.completions = prefs.getChildList("", { value: 0 });
+        },
 
         search: function search(context, noSuggest)
         {
diff --git a/content/options.js b/content/options.js
index ada77719..6ac9356c 100644
--- a/content/options.js
+++ b/content/options.js
@@ -678,11 +678,7 @@ function Options() //{{{
                         return;
                     }
 
-                    let prefs = Components.classes["@mozilla.org/preferences-service;1"]
-                                          .getService(Components.interfaces.nsIPrefBranch);
-                    context.keys = { text: function (pref) pref.item, description: function (pref) options.getPref(pref.item) };
-                    context.completions = prefs.getChildList("", { value: 0 });
-                    return;
+                    return completion.preference(context);
                 }
 
                 let opt = options.parseOpt(filter, modifiers);