diff --git a/chrome/content/zotero/preferences/preferences.js b/chrome/content/zotero/preferences/preferences.js
index 3d2c700ba..547fc190e 100644
--- a/chrome/content/zotero/preferences/preferences.js
+++ b/chrome/content/zotero/preferences/preferences.js
@@ -62,6 +62,7 @@ function init()
 	
 	if(window.arguments) {
 		_io = window.arguments[0];
+		if(_io.wrappedJSObject) _io = _io.wrappedJSObject;
 		
 		if(_io.pane) {
 			var pane = document.getElementById(_io.pane);
diff --git a/components/zotero-protocol-handler.js b/components/zotero-protocol-handler.js
index 253753b0a..f7b008fab 100644
--- a/components/zotero-protocol-handler.js
+++ b/components/zotero-protocol-handler.js
@@ -1062,8 +1062,9 @@ function ChromeExtensionHandler() {
 			if(s.length == 2) {
 				data.pane = s[1];
 			}
+			data.wrappedJSObject = data;
 			
-			if(Zotero.isFx4) {
+			if(Zotero.isFx4 || !Zotero.isMac) {
 				var win = Components.classes["@mozilla.org/appshell/window-mediator;1"]
 					.getService(Components.interfaces.nsIWindowMediator)
 					.getMostRecentWindow("navigator:browser");