diff --git a/chrome/content/zotero/tab.js b/chrome/content/zotero/tab.js
index 769f785b8..e498856ee 100644
--- a/chrome/content/zotero/tab.js
+++ b/chrome/content/zotero/tab.js
@@ -41,23 +41,30 @@ var ZoteroTab = new function()
 		if(browserIndex === -1) return;
 		
 		// initialize ZoteroPane and swap out old window ZoteroPane object
-		ZoteroPane.init();
-		
-		// swap window ZoteroPane with ZoteroPane from tab
-		window.ZoteroPane_Overlay = window.ZoteroPane;
-		window.ZoteroPane_Tab = ZoteroPane;
-		window.ZoteroPane = ZoteroPane;
+		if(window.ZoteroPane) {
+			window.ZoteroPane_Overlay = window.ZoteroPane;
+			window.ZoteroPane_Tab = ZoteroPane;
+			window.ZoteroPane = ZoteroPane;
+		} else {
+			window.addEventListener("load", function() {
+				window.ZoteroPane_Overlay = window.ZoteroPane;
+				window.ZoteroPane_Tab = ZoteroPane;
+				window.ZoteroPane = ZoteroPane;
+			}, false);
+		}
 		
 		// get tab for browser
 		var tab = window.gBrowser.tabs[browserIndex];
 		if(window.gBrowser.selectedTab === tab) {
 			// if tab is already selected, init now
+			ZoteroPane.init();
 			ZoteroPane.makeVisible();
 		} else {
 			// otherwise, add a handler to wait until this tab is selected
 			var listener = function(event) {
 				if(event.target !== tab) return;
 				window.gBrowser.tabContainer.removeEventListener("TabSelect", listener, false);
+				ZoteroPane.init();
 				ZoteroPane.makeVisible();
 			}
 			window.gBrowser.tabContainer.addEventListener("TabSelect", listener, false);