diff --git a/common/content/style.js b/common/content/style.js
index 4747f974..7825bb32 100644
--- a/common/content/style.js
+++ b/common/content/style.js
@@ -142,7 +142,7 @@ function Highlights(name, store)
     let styles = storage.styles;
 
     const Highlight = Struct("class", "selector", "filter", "default", "value");
-    Highlight.defaultValue("filter", function () "chrome://liberator/content/buffer.xhtml" + "," + config.styleableChrome);
+    Highlight.defaultValue("filter", function () ["chrome://liberator/content/buffer.xhtml"].concat(config.styleableChrome).join(","));
     Highlight.defaultValue("selector", function () self.selector(this.class));
     Highlight.defaultValue("value", function () this.default);
     Highlight.prototype.toString = function () "Highlight(" + this.class + ")\n\t" + [k + ": " + util.escapeString(v || "undefined") for ([k, v] in this)].join("\n\t");
diff --git a/muttator/content/config.js b/muttator/content/config.js
index af8f025d..f818c5ad 100644
--- a/muttator/content/config.js
+++ b/muttator/content/config.js
@@ -68,7 +68,8 @@ const config = (function () //{{{
         // focusContent() focuses this widget
         get mainWidget() this.isComposeWindow ? document.getElementById("content-frame") : GetThreadTree(),
         get visualbellWindow() document.getElementById(this.mainWindowId),
-        styleableChrome: "chrome://messenger/content/messenger.xul,chrome://messenger/content/messengercompose/messengercompose.xul",
+        styleableChrome: ["chrome://messenger/content/messenger.xul",
+                          "chrome://messenger/content/messengercompose/messengercompose.xul"],
 
         autocommands: [["DOMLoad",         "Triggered when a page's DOM content has fully loaded"],
                        ["FolderLoad",      "Triggered after switching folders in " + host],
diff --git a/vimperator/content/config.js b/vimperator/content/config.js
index bc3173d4..51da62ea 100644
--- a/vimperator/content/config.js
+++ b/vimperator/content/config.js
@@ -47,7 +47,7 @@ const config = { //{{{
     },
 
     get visualbellWindow() getBrowser().mPanelContainer,
-    styleableChrome: "chrome://browser/content/browser.xul",
+    styleableChrome: ["chrome://browser/content/browser.xul"],
 
     autocommands: [["BookmarkAdd",        "Triggered after a page is bookmarked"],
                    ["ColorScheme",        "Triggered after a color scheme has been loaded"],
diff --git a/xulmus/content/config.js b/xulmus/content/config.js
index 76030dc8..a1e9df38 100644
--- a/xulmus/content/config.js
+++ b/xulmus/content/config.js
@@ -51,7 +51,7 @@ const config = { //{{{
     // focusContent() focuses this widget gSongbirdWindowController takes care of the focus.
     get visualbellWindow() document.getElementById(this.mainWindowId),
 
-    styleableChrome: "chrome://gonzo/content/xul/mainplayer.xul",
+    styleableChrome: ["chrome://gonzo/content/xul/mainplayer.xul"],
 
     autocommands: [["BookmarkAdd",    "Triggered after a page is bookmarked"],
                    ["ColorScheme",    "Triggered after a color scheme has been loaded"],