diff --git a/chrome/content/zotero/zoteroPane.js b/chrome/content/zotero/zoteroPane.js
index 61dd79450d..0165c3ae70 100644
--- a/chrome/content/zotero/zoteroPane.js
+++ b/chrome/content/zotero/zoteroPane.js
@@ -2649,7 +2649,7 @@ var ZoteroPane = new function()
 	 *  (e.g. meta-click == new background tab, meta-shift-click == new front tab,
 	 *  shift-click == new window, no modifier == frontmost tab
 	 */
-	function loadURI(uris, event, data) {
+	function loadURI(uris, event) {
 		if(typeof uris === "string") {
 			uris = [uris];
 		}
@@ -3383,7 +3383,7 @@ var ZoteroPane = new function()
 				
 				if (!externalViewer) {
 					var url = 'zotero://attachment/' + itemID + '/';
-					this.loadURI(url, event, { attachmentID: itemID});
+					this.loadURI(url, event);
 				}
 				else {
 					// Some platforms don't have nsILocalFile.launch, so we just