diff --git a/chrome/content/zotero-platform/mac/overlay.css b/chrome/content/zotero-platform/mac/overlay.css
index 4f0bef145..e02cb1d70 100644
--- a/chrome/content/zotero-platform/mac/overlay.css
+++ b/chrome/content/zotero-platform/mac/overlay.css
@@ -27,10 +27,6 @@
 	padding-left: 0;
 }
 
-:root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) .zotero-tb-button, .zotero-tb-button[disabled="true"]{
-	opacity: 0.7;
-}
-
 .zotero-tb-button:-moz-window-inactive {
 	opacity: 0.7;
 }
@@ -128,7 +124,7 @@
 	display: none;
 }
 
-#zotero-pane[ignoreActiveAttribute] #zotero-view-tabbox > tabs > tab {
+#zotero-pane #zotero-view-tabbox > tabs > tab {
 	-moz-box-orient: vertical;
 	-moz-box-align: center;
 	-moz-appearance: toolbarbutton;
@@ -138,7 +134,7 @@
 	padding: 3px 1px 3px 1px;
 }
 
-#zotero-pane[ignoreActiveAttribute] #zotero-view-tabbox > tabs > tab > hbox .tab-text {
+#zotero-pane #zotero-view-tabbox > tabs > tab > hbox .tab-text {
 	font-size: 11px;
 	font-weight: bold;
 	margin: 2px 7px 2px 9px !important;
@@ -146,157 +142,15 @@
 }
 
 /* This seems to be necessary to center the tabs. Not sure why. */
-#zotero-pane[ignoreActiveAttribute] #zotero-view-tabbox > tabs > tab:last-of-type > hbox .tab-text {
+#zotero-pane #zotero-view-tabbox > tabs > tab:last-of-type > hbox .tab-text {
 	margin: 2px 9px 2px 9px !important;
 }
 
-#zotero-pane[ignoreActiveAttribute] #zotero-view-tabbox > tabs > tab[selected=true] > hbox .tab-text {
+#zotero-pane #zotero-view-tabbox > tabs > tab[selected=true] > hbox .tab-text {
 	color: #FFF !important;
 	text-shadow: rgba(0, 0, 0, 0.4) 0 1px;
 }
 
-/** RULES FOR FX 3.6 **/
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab > hbox .tab-text {
-  text-shadow: rgba(255, 255, 255, 0.4) 0 1px !important;
-  font-size: 11px;
-  font-weight: bold;
-}
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab:active:hover > hbox > .tab-text,
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab[selected=true] > hbox > .tab-text {
-  text-shadow: none !important;
-}
-
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab {
-  -moz-box-orient: vertical;
-  -moz-box-align: center;
-  -moz-appearance: none;
-  margin: 0;
-  padding: 3px 0 1px;
-  background-color: transparent;
-  border: solid transparent;
-  border-width: 0 4px 0 5px;
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-middle.png") 0 4 0 5 repeat stretch;
-}
-
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab:active:hover {
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-middle-down.png") 0 4 0 5 repeat stretch;
-  text-shadow: none !important;
-}
-
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab[selected=true] {
-  color: #FFF !important;
-  text-shadow: rgba(0, 0, 0, 0.4) 0 1px;
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-middle-selected.png") 0 4 0 5 repeat stretch;
-}
-
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab[selected=true]:active:hover {
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-middle-selected-down.png") 0 4 0 5 repeat stretch;
-}
-
-:root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > * {
-  color: #7C7C7C !important;
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-middle-inactive.png") 0 4 0 5 repeat stretch;
-}
-
-:root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab[selected=true] {
-  color: #FFF !important;
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-middle-selected-inactive.png") 0 4 0 5 repeat stretch;
-}
-
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > :first-child,
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > [first-visible],
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > :last-child,
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > [last-visible] {
-  border-width: 0 4px 0 6px;
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-left.png") 0 4 0 6 repeat stretch;
-}
-
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > :first-child:active:hover,
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > [first-visible]:active:hover,
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > :last-child:active:hover,
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > [last-visible]:active:hover {
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-left-down.png") 0 4 0 6 repeat stretch;
-}
-
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab:first-child[selected=true],
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab[first-visible][selected=true],
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > tab:last-child[selected=true],
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > tab[last-visible][selected=true] {
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-left-selected.png") 0 4 0 6 repeat stretch;
-}
-
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab:first-child[selected=true]:active:hover,
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab[first-visible][selected=true]:active:hover,
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > tab:last-child[selected=true]:active:hover,
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > tab[last-visible][selected=true]:active:hover {
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-left-selected-down.png") 0 4 0 6 repeat stretch;
-}
-
-#zotero-pane:not([ignoreActiveAttribute]) :root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > :first-child,
-#zotero-pane:not([ignoreActiveAttribute]) :root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > [first-visible],
-#zotero-pane:not([ignoreActiveAttribute]) :root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > :last-child,
-#zotero-pane:not([ignoreActiveAttribute]) :root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > [last-visible] {
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-left-inactive.png") 0 4 0 6 repeat stretch;
-}  
-
-:root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab:first-child[selected=true],
-:root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab[first-visible][selected=true],
-:root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > tab:last-child[selected=true],
-:root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > tab[last-visible][selected=true] {
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-left-selected-inactive.png") 0 4 0 6 repeat stretch;
-}
-
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > :last-child,
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > [last-visible],
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > :first-child,
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > [first-visible] {
-  border-width: 0 6px 0 5px;
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-right.png") 0 6 0 5 repeat stretch;
-}
-
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > :last-child:active:hover,
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > [last-visible]:active:hover,
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > :first-child:active:hover,
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > [first-visible]:active:hover {
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-right-down.png") 0 6 0 5 repeat stretch;
-}
-
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab:last-child[selected=true],
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab[last-visible][selected=true],
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > tab:first-child[selected=true],
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > tab[first-visible][selected=true] {
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-right-selected.png") 0 6 0 5 repeat stretch;
-}
-
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab:last-child[selected=true]:active:hover,
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab[last-visible][selected=true]:active:hover,
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > tab:first-child[selected=true]:active:hover,
-#zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > tab[first-visible][selected=true]:active:hover {
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-right-selected-down.png") 0 6 0 5 repeat stretch;
-}
-
-#zotero-pane:not([ignoreActiveAttribute]) :root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > :last-child,
-#zotero-pane:not([ignoreActiveAttribute]) :root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > [last-visible],
-#zotero-pane:not([ignoreActiveAttribute]) :root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > :first-child,
-#zotero-pane:not([ignoreActiveAttribute]) :root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > [first-visible] {
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-right-inactive.png") 0 6 0 5 repeat stretch;
-}
-
-#zotero-view-tabbox:-moz-window-inactive > tabs > tab:last-child[selected=true],
-#zotero-view-tabbox:-moz-window-inactive > tabs > tab[last-visible][selected=true],
-#zotero-view-tabbox:-moz-window-inactive > tabs[chromedir=rtl] > tab:first-child[selected=true],
-#zotero-view-tabbox:-moz-window-inactive > tabs[chromedir=rtl] > tab[first-visible][selected=true] {
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-right-selected-inactive.png") 0 6 0 5 repeat stretch;
-}
-
-:root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab:last-child[selected=true],
-:root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs > tab[last-visible][selected=true],
-:root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > tab:first-child[selected=true],
-:root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-view-tabbox > tabs[chromedir=rtl] > tab[first-visible][selected=true] {
-  -moz-border-image: url("chrome://zotero/skin/mac/viewbutton-right-selected-inactive.png") 0 6 0 5 repeat stretch;
-}
-/** END RULES FOR FX 3.6 **/
-
 #zotero-collections-tree {
 	-moz-appearance: none;
 	border: none;
@@ -310,10 +164,6 @@
 	background-color: rgb(232, 232, 232);
 }
 
-:root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) #zotero-collections-tree {
-	background-color: rgb(232, 232, 232);
-}
-
 #zotero-collections-tree treechildren::-moz-tree-row {
 	background-color: transparent;
 	border-color: transparent;
@@ -329,11 +179,6 @@
 	border-top: 1px solid #979797;
 }
 
-:root:not([active]) #zotero-pane:not([ignoreActiveAttribute]) treechildren::-moz-tree-cell(selected) {   
-	background: -moz-linear-gradient(top, #B4B4B4, #8A8A8A) repeat-x;
-	border-top: 1px solid #979797;
-}
-
 #zotero-collections-tree treechildren::-moz-tree-cell(selected, focus) {  
   background: -moz-linear-gradient(top, #6494D4, #2559AC) repeat-x;
   border-top: 1px solid #5382C5;
diff --git a/chrome/content/zotero/overlay.js b/chrome/content/zotero/overlay.js
index a20a12631..168d86d11 100644
--- a/chrome/content/zotero/overlay.js
+++ b/chrome/content/zotero/overlay.js
@@ -29,7 +29,7 @@
 var ZoteroOverlay = new function()
 {
 	const DEFAULT_ZPANE_HEIGHT = 300;
-	var toolbarCollapseState, isFx36, showInPref;	
+	var toolbarCollapseState, showInPref;	
 	var zoteroPane, zoteroSplitter;
 	var _stateBeforeReload = false;
 	
@@ -44,36 +44,31 @@ var ZoteroOverlay = new function()
 		ZoteroPane_Overlay = ZoteroPane;
 		ZoteroPane.init();
 		
-		var appInfo = Components.classes["@mozilla.org/xre/app-info;1"]
-						.getService(Components.interfaces.nsIXULAppInfo);
-		isFx36 = appInfo.platformVersion.indexOf('1.9') === 0;
-		
 		// Open Zotero app tab, if in Fx 4 and requested by pref
 		showInPref = Components.classes["@mozilla.org/preferences-service;1"]
 							.getService(Components.interfaces.nsIPrefService)
 							.getBranch('extensions.zotero.').getIntPref('showIn');
 		this.isTab = showInPref !== 1;
-		if(!isFx36) {
-			var observerService = Components.classes["@mozilla.org/observer-service;1"]
-				.getService(Components.interfaces.nsIObserverService);
-			var zoteroObserver = function(subject, topic, data) {
-				if(subject != window) return;
-				observerService.removeObserver(this, "browser-delayed-startup-finished");
-				if(showInPref === 3) {
-					var tabbar = document.getElementById("TabsToolbar");
-					if(tabbar && window.getComputedStyle(tabbar).display !== "none") {
-						// load Zotero as a tab, if it isn't loading by default
-						ZoteroOverlay.loadZoteroTab(true);
-					}
-				} else if(showInPref === 1) {
-					// close Zotero as a tab, in case it was pinned
-					var zoteroTab = ZoteroOverlay.findZoteroTab();
-					if(zoteroTab) gBrowser.removeTab(zoteroTab);
+
+		var observerService = Components.classes["@mozilla.org/observer-service;1"]
+			.getService(Components.interfaces.nsIObserverService);
+		var zoteroObserver = function(subject, topic, data) {
+			if(subject != window) return;
+			observerService.removeObserver(this, "browser-delayed-startup-finished");
+			if(showInPref === 3) {
+				var tabbar = document.getElementById("TabsToolbar");
+				if(tabbar && window.getComputedStyle(tabbar).display !== "none") {
+					// load Zotero as a tab, if it isn't loading by default
+					ZoteroOverlay.loadZoteroTab(true);
 				}
-			};
-			
-			observerService.addObserver(zoteroObserver, "browser-delayed-startup-finished", false);
-		}
+			} else if(showInPref === 1) {
+				// close Zotero as a tab, in case it was pinned
+				var zoteroTab = ZoteroOverlay.findZoteroTab();
+				if(zoteroTab) gBrowser.removeTab(zoteroTab);
+			}
+		};
+		
+		observerService.addObserver(zoteroObserver, "browser-delayed-startup-finished", false);
 		
 		// Make Zotero icon visible, if requested
 		var prefBranch = Components.classes["@mozilla.org/preferences-service;1"]
@@ -149,9 +144,7 @@ var ZoteroOverlay = new function()
 		}
 		
 		// Hide browser chrome on Zotero tab
-		if(Zotero.isFx4) {
-			XULBrowserWindow.inContentWhitelist.push("chrome://zotero/content/tab.xul");
-		}
+		XULBrowserWindow.inContentWhitelist.push("chrome://zotero/content/tab.xul");
 		
 		// Close pane if connector is enabled
 		ZoteroPane_Local.addReloadListener(function() {
@@ -309,7 +302,7 @@ var ZoteroOverlay = new function()
 		// If no existing tab, add a new tab
 		if(!tab) tab = gBrowser.addTab(ZOTERO_TAB_URL);
 		// Pin tab
-		if(!isFx36 && showInPref == 3) gBrowser.pinTab(tab);
+		if(showInPref == 3) gBrowser.pinTab(tab);
 		// If requested, activate tab
 		if(!background) gBrowser.selectedTab = tab;
 	}
diff --git a/chrome/content/zotero/xpcom/fulltext.js b/chrome/content/zotero/xpcom/fulltext.js
index 2796fc119..3d65e6f23 100644
--- a/chrome/content/zotero/xpcom/fulltext.js
+++ b/chrome/content/zotero/xpcom/fulltext.js
@@ -429,12 +429,7 @@ Zotero.Fulltext = new function(){
 			
 			var args = [file.path, infoFile.path];
 			try {
-				if (!Zotero.isFx36) {
-					proc.runw(true, args, args.length);
-				}
-				else {
-					proc.run(true, args, args.length);
-				}
+				proc.runw(true, args, args.length);
 				var totalPages = this.getTotalPagesFromFile(itemID);
 			}
 			catch (e) {
@@ -465,12 +460,7 @@ Zotero.Fulltext = new function(){
 		}
 		args.push(file.path, cacheFile.path);
 		try {
-			if (!Zotero.isFx36) {
-				proc.runw(true, args, args.length);
-			}
-			else {
-				proc.run(true, args, args.length);
-			}
+			proc.runw(true, args, args.length);
 		}
 		catch (e) {
 			Zotero.debug("Error running pdftotext");
diff --git a/chrome/content/zotero/xpcom/http.js b/chrome/content/zotero/xpcom/http.js
index 59e84aa5e..42ff2d2b5 100644
--- a/chrome/content/zotero/xpcom/http.js
+++ b/chrome/content/zotero/xpcom/http.js
@@ -94,35 +94,15 @@ Zotero.HTTP = new function() {
 			return false;
 		}
 		
-		// Workaround for "Accept third-party cookies" being off in Firefox 3.0.1
-		// https://www.zotero.org/trac/ticket/1070
-		if (Zotero.isFx30) {
-			const Cc = Components.classes;
-			const Ci = Components.interfaces;
-			var ds = Cc["@mozilla.org/webshell;1"].
-						createInstance(Components.interfaces.nsIDocShellTreeItem).
-						QueryInterface(Ci.nsIInterfaceRequestor);
-			ds.itemType = Ci.nsIDocShellTreeItem.typeContent;
-			var xmlhttp = Cc["@mozilla.org/xmlextras/xmlhttprequest;1"].
-							createInstance(Ci.nsIXMLHttpRequest);
-			xmlhttp.mozBackgroundRequest = true;
-			xmlhttp.open("POST", url, true);
-			xmlhttp.channel.loadGroup = ds.getInterface(Ci.nsILoadGroup);
-			xmlhttp.channel.loadFlags |= Ci.nsIChannel.LOAD_DOCUMENT_URI;
-		}
-		else {
-			var xmlhttp = Components.classes["@mozilla.org/xmlextras/xmlhttprequest;1"]
-						.createInstance();
-			// Prevent certificate/authentication dialogs from popping up
-			xmlhttp.mozBackgroundRequest = true;
-			xmlhttp.open('POST', url, true);
-			// Send cookie even if "Allow third-party cookies" is disabled (>=Fx3.6 only)
-			if (!Zotero.isFx35) {
-				var channel = xmlhttp.channel;
-				channel.QueryInterface(Components.interfaces.nsIHttpChannelInternal);
-				channel.forceAllowThirdPartyCookie = true;
-			}
-		}
+		var xmlhttp = Components.classes["@mozilla.org/xmlextras/xmlhttprequest;1"]
+					.createInstance();
+		// Prevent certificate/authentication dialogs from popping up
+		xmlhttp.mozBackgroundRequest = true;
+		xmlhttp.open('POST', url, true);
+		// Send cookie even if "Allow third-party cookies" is disabled (>=Fx3.6 only)
+		var channel = xmlhttp.channel;
+		channel.QueryInterface(Components.interfaces.nsIHttpChannelInternal);
+		channel.forceAllowThirdPartyCookie = true;
 		
 		if (headers) {
 			if (typeof headers == 'string') {
@@ -186,34 +166,15 @@ Zotero.HTTP = new function() {
 		
 		// Workaround for "Accept third-party cookies" being off in Firefox 3.0.1
 		// https://www.zotero.org/trac/ticket/1070
-		if (Zotero.isFx30) {
-			const Cc = Components.classes;
-			const Ci = Components.interfaces;
-			var ds = Cc["@mozilla.org/webshell;1"].
-						createInstance(Components.interfaces.nsIDocShellTreeItem).
-						QueryInterface(Ci.nsIInterfaceRequestor);
-			ds.itemType = Ci.nsIDocShellTreeItem.typeContent;
-			var xmlhttp = Cc["@mozilla.org/xmlextras/xmlhttprequest;1"].
-							createInstance(Ci.nsIXMLHttpRequest);
-			// Prevent certificate/authentication dialogs from popping up
-			xmlhttp.mozBackgroundRequest = true;
-			xmlhttp.open("HEAD", url, true);
-			xmlhttp.channel.loadGroup = ds.getInterface(Ci.nsILoadGroup);
-			xmlhttp.channel.loadFlags |= Ci.nsIChannel.LOAD_DOCUMENT_URI;
-		}
-		else {
-			var xmlhttp = Components.classes["@mozilla.org/xmlextras/xmlhttprequest;1"]
-							.createInstance();
-			// Prevent certificate/authentication dialogs from popping up
-			xmlhttp.mozBackgroundRequest = true;
-			xmlhttp.open('HEAD', url, true);
-			// Send cookie even if "Allow third-party cookies" is disabled (>=Fx3.6 only)
-			if (!Zotero.isFx35) {
-				var channel = xmlhttp.channel;
-				channel.QueryInterface(Components.interfaces.nsIHttpChannelInternal);
-				channel.forceAllowThirdPartyCookie = true;
-			}
-		}
+		var xmlhttp = Components.classes["@mozilla.org/xmlextras/xmlhttprequest;1"]
+						.createInstance();
+		// Prevent certificate/authentication dialogs from popping up
+		xmlhttp.mozBackgroundRequest = true;
+		xmlhttp.open('HEAD', url, true);
+		// Send cookie even if "Allow third-party cookies" is disabled (>=Fx3.6 only)
+		var channel = xmlhttp.channel;
+		channel.QueryInterface(Components.interfaces.nsIHttpChannelInternal);
+		channel.forceAllowThirdPartyCookie = true;
 		
 		if (requestHeaders) {
 			for (var header in requestHeaders) {
@@ -556,7 +517,7 @@ Zotero.HTTP = new function() {
 		if(typeof(urls) == "string") urls = [urls];
 		
 		var prevUrl;
-		var loadEvent = Zotero.isFx2 ? "load" : "pageshow";
+		var loadEvent = "pageshow";
 		
 		var hiddenBrowser = Zotero.Browser.createHiddenBrowser();
 		hiddenBrowser.addEventListener(loadEvent, onLoad, true);
diff --git a/chrome/content/zotero/xpcom/translation/translate.js b/chrome/content/zotero/xpcom/translation/translate.js
index 783c94a51..a630b7968 100644
--- a/chrome/content/zotero/xpcom/translation/translate.js
+++ b/chrome/content/zotero/xpcom/translation/translate.js
@@ -1294,10 +1294,6 @@ Zotero.Translate.Base.prototype = {
 	 * @param {Integer} level Log level (1-5, higher numbers are higher priority)
 	 */
 	"_debug":function(string, level) {
-		if(typeof string === "object" && Zotero.isFx36 && !Zotero.isBookmarklet) {
-			string = new XPCSafeJSObjectWrapper(string);
-		}
-		
 		if(level !== undefined && typeof level !== "number") {
 			Zotero.debug("debug: level must be an integer");
 			return;
diff --git a/chrome/content/zotero/xpcom/zotero.js b/chrome/content/zotero/xpcom/zotero.js
index ce35b6a39..9c59539e5 100644
--- a/chrome/content/zotero/xpcom/zotero.js
+++ b/chrome/content/zotero/xpcom/zotero.js
@@ -1757,12 +1757,7 @@ const ZOTERO_CONFIG = {
 			for each(var menuitem in menupopup.childNodes) {
 				if (menuitem.id.substr(prefixLen) == mode) {
 					menuitem.setAttribute('checked', true);
-					if (Zotero.isFx36) {
-						searchBox.emptytext = modes[mode].label;
-					}
-					else {
-						searchBox.placeholder = modes[mode].label;
-					}
+					searchBox.placeholder = modes[mode].label;
 					return;
 				}
 			}
@@ -1803,12 +1798,7 @@ const ZOTERO_CONFIG = {
 		button.appendChild(menupopup);
 		hbox.insertBefore(button, input);
 		
-		if (Zotero.isFx36) {
-			searchBox.emptytext = modes[mode].label;
-		}
-		else {
-			searchBox.placeholder = modes[mode].label;
-		}
+		searchBox.placeholder = modes[mode].label;
 		
 		// If Alt-Up/Down, show popup
 		searchBox.addEventListener("keypress", function(event) {
diff --git a/chrome/content/zotero/zoteroPane.js b/chrome/content/zotero/zoteroPane.js
index a198ef2e5..0c58c4825 100644
--- a/chrome/content/zotero/zoteroPane.js
+++ b/chrome/content/zotero/zoteroPane.js
@@ -124,13 +124,6 @@ var ZoteroPane = new function()
 			document.getElementById('zotero-pane-stack').setAttribute('platform', 'win');
 		}
 		
-		if(Zotero.isFx4 || window.ZoteroTab) {
-			// hack, since Fx 4 no longer sets active, and the reverse in polarity of the preferred
-			// property makes things painful to handle otherwise
-			// DEBUG: remove this once we only support Fx 4
-			zp.setAttribute("ignoreActiveAttribute", "true");
-		}
-		
 		// register an observer for Zotero reload
 		observerService = Components.classes["@mozilla.org/observer-service;1"]
 					  .getService(Components.interfaces.nsIObserverService);
@@ -3469,12 +3462,7 @@ var ZoteroPane = new function()
 				proc.init(exec);
 				
 				var args = [file.path];
-				if (!Zotero.isFx36) {
-					proc.runw(true, args, args.length);
-				}
-				else {
-					proc.run(true, args, args.length);
-				}
+				proc.runw(true, args, args.length);
 			}
 			catch (e) {
 				Zotero.debug(e);
@@ -3538,12 +3526,7 @@ var ZoteroPane = new function()
 			proc.init(exec);
 			
 			var args = [url];
-			if (!Zotero.isFx36) {
-				proc.runw(true, args, args.length);
-			}
-			else {
-				proc.run(true, args, args.length);
-			}
+			proc.runw(true, args, args.length);
 		}
 	}