diff --git a/common/content/dactyl.js b/common/content/dactyl.js
index 0505f40a..1b45c777 100644
--- a/common/content/dactyl.js
+++ b/common/content/dactyl.js
@@ -298,7 +298,7 @@ const Dactyl = Module("dactyl", {
         if (!context)
             context = userContext;
         context[EVAL_STRING] = str;
-        return Cu.evalInSandbox("with (window) { eval(" + EVAL_STRING + ") }", context, "1.8", fileName, lineNumber);
+        return Cu.evalInSandbox("eval('with (window) {'+" + EVAL_STRING + "+'}')", context, "1.8", fileName, lineNumber);
     },
 
     /**
diff --git a/common/content/io.js b/common/content/io.js
index d373120d..43d20ec6 100644
--- a/common/content/io.js
+++ b/common/content/io.js
@@ -160,7 +160,7 @@ const IO = Module("io", {
     getRuntimeDirectories: function (name) {
         let dirs = options["runtimepath"];
 
-        dirs = dirs.map(function (dir) File.joinPaths(dir, name, this.cwd))
+        dirs = dirs.map(function (dir) File.joinPaths(dir, name, this.cwd), this)
                    .filter(function (dir) dir.exists() && dir.isDirectory() && dir.isReadable());
         return dirs;
     },
diff --git a/common/modules/highlight.jsm b/common/modules/highlight.jsm
index 96a142e0..d5d7f711 100644
--- a/common/modules/highlight.jsm
+++ b/common/modules/highlight.jsm
@@ -147,11 +147,13 @@ const Highlights = Module("Highlight", {
      *
      * @param {string} class
      */
-    selector: function (class_)
-        class_.replace(/(^|\s)([A-Z]\w+)\b/g,
+    selector: function (class_) {
+        const self = this;
+        return class_.replace(/(^|\s)([A-Z]\w+)\b/g,
                 function (m, n1, hl) n1 +
-                    (this.highlight[hl] && this.highlight[hl].class != class_
-                        ? this.highlight[hl] : "[dactyl|highlight~=" + hl + "]")),
+                    (self.highlight[hl] && self.highlight[hl].class != class_
+                        ? self.highlight[hl] : "[dactyl|highlight~=" + hl + "]"));
+    },
 
     /**
      * Clears all highlighting rules. Rules with default values are
diff --git a/common/modules/storage.jsm b/common/modules/storage.jsm
index 0cd800e6..008fcedc 100644
--- a/common/modules/storage.jsm
+++ b/common/modules/storage.jsm
@@ -282,7 +282,7 @@ const File = Class("File", {
                 return null;
             }
         }
-        let self = XPCSafeJSObjectWrapper(file);
+        let self = XPCNativeWrapper(file);
         self.__proto__ = File.prototype;
         return self;
     },