diff --git a/common/content/configbase.js b/common/content/configbase.js
index ce8d5d55..7519e7c1 100644
--- a/common/content/configbase.js
+++ b/common/content/configbase.js
@@ -32,6 +32,9 @@ const ConfigBase = Class(ModuleBase, {
                  {"}"}</>);
             img = null;
         };
+
+        if (util.haveGecko("2b"))
+            this.features.push("Gecko2");
     },
 
     styleHelp: function () {
diff --git a/common/content/dactyl.js b/common/content/dactyl.js
index 6a2bcaf5..34c9627f 100644
--- a/common/content/dactyl.js
+++ b/common/content/dactyl.js
@@ -1284,7 +1284,9 @@ const Dactyl = Module("dactyl", {
 
                     styles.addSheet(true, "taboptions", "chrome://*",
                         classes.length ? classes.join(",") + "{ display: none; }" : "");
-                }
+                },
+                validator: function (opts) dactyl.has("Gecko2") ||
+                    Option.validIf(!/[nN]/.test(opts), "Tab numbering not available in this " + config.host + " version")
             }
         ].filter(function (group) !group.feature || dactyl.has(group.feature));
 
diff --git a/common/content/finder.js b/common/content/finder.js
index 34d95bc9..93ca6a6d 100644
--- a/common/content/finder.js
+++ b/common/content/finder.js
@@ -77,7 +77,7 @@ const RangeFinder = Module("rangefinder", {
     },
 
     findAgain: function (reverse) {
-        if (!this.rangeFind)
+        if (!this.rangeFind || this.rangeFind.stale)
             this.find(this.lastFindPattern);
         else if (!this.rangeFind.find(null, reverse))
             dactyl.echoerr("E486: Pattern not found: " + this.lastFindPattern);
diff --git a/common/content/options.js b/common/content/options.js
index ff527503..36bddf85 100644
--- a/common/content/options.js
+++ b/common/content/options.js
@@ -8,7 +8,11 @@
 
 /** @scope modules */
 
-let ValueError = Class("ValueError", Error);
+let ValueError = Class("ValueError", Error, {
+    init: function (message) {
+        update(this, Error(message));
+    }
+});
 
 // do NOT create instances of this class yourself, use the helper method
 // options.add() instead