diff --git a/common/content/buffer.js b/common/content/buffer.js
index 46fb9988..74621395 100644
--- a/common/content/buffer.js
+++ b/common/content/buffer.js
@@ -208,7 +208,6 @@ const Buffer = Module("buffer", {
         }
 
         if (doc instanceof HTMLDocument) {
-
             if (doc.defaultView.frameElement) {
                 // document is part of a frameset
 
@@ -1504,12 +1503,9 @@ const Buffer = Module("buffer", {
               .QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIXULWindow)
               .XULBrowserWindow = this.progressListener;
 
-        let appContent = document.getElementById("appcontent");
-        if (appContent) {
-            events.addSessionListener(appContent, "DOMContentLoaded", this.closure.onDOMContentLoaded, true);
-            events.addSessionListener(appContent, "load", this.closure.onPageLoad, true);
-            events.addSessionListener(appContent, "scroll", this.closure._updateBufferPosition, false);
-        }
+        events.addSessionListener(config.browser, "DOMContentLoaded", this.closure.onDOMContentLoaded, true);
+        events.addSessionListener(config.browser, "load", this.closure.onPageLoad, true);
+        events.addSessionListener(config.browser, "scroll", this.closure._updateBufferPosition, false);
     },
     mappings: function () {
         var myModes = config.browserModes;
diff --git a/common/content/events.js b/common/content/events.js
index d9e70e8a..c121882e 100644
--- a/common/content/events.js
+++ b/common/content/events.js
@@ -1113,11 +1113,11 @@ const Events = Module("events", {
             function () { commandline.open(":", "", modes.EX); });
 
         // focus events
-        mappings.add([modes.NORMAL, modes.PLAYER, modes.VISUAL, modes.CARET],
+        mappings.add([modes.NORMAL, modes.PLAYER, modes.VISUAL, modes.CARET].filter(util.identity),
             ["<Tab>"], "Advance keyboard focus",
             function () { document.commandDispatcher.advanceFocus(); });
 
-        mappings.add([modes.NORMAL, modes.PLAYER, modes.VISUAL, modes.CARET, modes.INSERT, modes.TEXT_EDIT],
+        mappings.add([modes.NORMAL, modes.PLAYER, modes.VISUAL, modes.CARET, modes.INSERT, modes.TEXT_EDIT].filter(util.identity),
             ["<S-Tab>"], "Rewind keyboard focus",
             function () { document.commandDispatcher.rewindFocus(); });
 
@@ -1134,12 +1134,12 @@ const Events = Module("events", {
             function () { return; });
 
         // macros
-        mappings.add([modes.NORMAL, modes.PLAYER, modes.MESSAGE],
+        mappings.add([modes.NORMAL, modes.PLAYER, modes.MESSAGE].filter(util.identity),
             ["q"], "Record a key sequence into a macro",
             function (arg) { events.startRecording(arg); },
             { arg: true });
 
-        mappings.add([modes.NORMAL, modes.PLAYER, modes.MESSAGE],
+        mappings.add([modes.NORMAL, modes.PLAYER, modes.MESSAGE].filter(util.identity),
             ["@"], "Play a macro",
             function (count, arg) {
                 count = Math.max(count, 1);
diff --git a/common/content/mappings.js b/common/content/mappings.js
index 1a28a899..2045e468 100644
--- a/common/content/mappings.js
+++ b/common/content/mappings.js
@@ -32,6 +32,8 @@
 const Map = Class("Map", {
     init: function (modes, keys, description, action, extraInfo) {
         modes = Array.concat(modes).map(function (m) isObject(m) ? m.mask : m);
+        if (!modes.every(util.identity))
+            throw Error("Invalid modes");
 
         this.id = ++Map.id;
         this.modes = modes;
diff --git a/common/content/modes.js b/common/content/modes.js
index f9d3596a..ad9cd942 100644
--- a/common/content/modes.js
+++ b/common/content/modes.js
@@ -29,7 +29,7 @@ const Modes = Module("modes", {
             }
         });
 
-        this._mainModes = [this.NONE];
+        this._mainModes = [];
         this._lastMode = 0;
         this._modeMap = {};