diff --git a/extensions/alternate-tab/extension.js b/extensions/alternate-tab/extension.js
index c3ef698d..8b4cc744 100644
--- a/extensions/alternate-tab/extension.js
+++ b/extensions/alternate-tab/extension.js
@@ -54,6 +54,8 @@ function enable() {
 }
 
 function disable() {
+    var prop;
+
     setKeybinding('switch-applications', Lang.bind(Main.wm, Main.wm._startAppSwitcher));
     setKeybinding('switch-group', Lang.bind(Main.wm, Main.wm._startAppSwitcher));
     setKeybinding('switch-applications-backward', Lang.bind(Main.wm, Main.wm._startAppSwitcher));
diff --git a/extensions/native-window-placement/extension.js b/extensions/native-window-placement/extension.js
index 2fea9479..b0dcc5d5 100644
--- a/extensions/native-window-placement/extension.js
+++ b/extensions/native-window-placement/extension.js
@@ -480,6 +480,8 @@ function removeInjection(object, injection, name) {
 }
 
 function disable() {
+    var i;
+
     for (i in workspaceInjections)
         removeInjection(Workspace.Workspace.prototype, workspaceInjections, i);
     for (i in winInjections)
diff --git a/extensions/window-list/extension.js b/extensions/window-list/extension.js
index d5ac261f..2980fbe9 100644
--- a/extensions/window-list/extension.js
+++ b/extensions/window-list/extension.js
@@ -842,6 +842,8 @@ function enable() {
 }
 
 function disable() {
+    var prop;
+
     if (!windowList)
         return;