diff --git a/chrome/content/scaffold/content.js b/chrome/content/scaffold/content.js
new file mode 100644
index 0000000000..c042dba1cb
--- /dev/null
+++ b/chrome/content/scaffold/content.js
@@ -0,0 +1,15 @@
+addMessageListener('Scaffold:GetDocument', {
+	receiveMessage() {
+		dump('received document request\n')
+		sendAsyncMessage('Scaffold:Document', {
+			html: new XMLSerializer().serializeToString(content.document),
+			url: content.location.href
+		});
+	}
+});
+
+function onLoad() {
+	sendAsyncMessage('Scaffold:Load', { url: content.location.href });
+}
+
+addEventListener('load', onLoad, true);
diff --git a/chrome/content/scaffold/load.js b/chrome/content/scaffold/load.js
index 62067c1455..6e1f54a277 100644
--- a/chrome/content/scaffold/load.js
+++ b/chrome/content/scaffold/load.js
@@ -24,12 +24,14 @@
 */
 
 var Scaffold_Load = new function() {
-	this.onLoad = Zotero.Promise.coroutine(function* () {
+	this.onLoad = async function () {
+		document.addEventListener('dialogaccept', () => this.accept());
+
 		var listitem, translator, listcell, set;
 		var listbox = document.getElementById("listbox");
 		
 		listbox.addEventListener('dblclick', () => {
-			var translatorID = document.getElementById("listbox").selectedItem.getUserData("zotero-id");
+			var translatorID = document.getElementById("listbox").selectedItem.dataset.zoteroID;
 			if (!translatorID) return;
 			this.accept();
 			window.close();
@@ -42,44 +44,48 @@ var Scaffold_Load = new function() {
 		var url = window.arguments[0].url;
 		var rootUrl = window.arguments[0].rootUrl
 		url = Zotero.Proxies.proxyToProper(url);
-		translators["Matching Translators"] = (yield translatorProvider.getWebTranslatorsForLocation(url, rootUrl))[0];
-		translators["Web Translators"] = (yield translatorProvider.getAllForType("web"))
+		translators["Matching Translators"] = (await translatorProvider.getWebTranslatorsForLocation(url, rootUrl))[0];
+		translators["Web Translators"] = (await translatorProvider.getAllForType("web"))
 			.sort((a, b) => a.label.localeCompare(b.label));
-		translators["Import Translators"] = (yield translatorProvider.getAllForType("import"))
+		translators["Import Translators"] = (await translatorProvider.getAllForType("import"))
 			.sort((a, b) => a.label.localeCompare(b.label));
-		translators["Export Translators"] = (yield translatorProvider.getAllForType("export"))
+		translators["Export Translators"] = (await translatorProvider.getAllForType("export"))
 			.sort((a, b) => a.label.localeCompare(b.label));
-		translators["Search Translators"] = (yield translatorProvider.getAllForType("search"))
+		translators["Search Translators"] = (await translatorProvider.getAllForType("search"))
 			.sort((a, b) => a.label.localeCompare(b.label));
 
 		for (set in translators) {
 			// Make a separator
-			listitem = document.createElement("listitem");
+			listitem = document.createXULElement("richlistitem");
 			listitem.setAttribute("disabled", true);
-			listitem.setAttribute("label", set);
+			// Need to set this to disable up/down keys selecting:
+			listitem.style.MozUserInput = 'none';
+			listitem.append(set);
 			listbox.appendChild(listitem);
 			for (var j=0; j<translators[set].length; j++) {
 				var translator = translators[set][j];
-				listitem = document.createElement("listitem");
-				// set label for type-to-find functionality. This is not displayed.
-				listitem.setAttribute("label", translator.label);
+				listitem = document.createXULElement("richlistitem");
+				// set search label for type-to-find functionality. This is not displayed.
+				listitem.searchLabel = translator.label;
 				// And the ID goes in DOM user data
-				listitem.setUserData("zotero-id", translator.translatorID, null);
+				listitem.dataset.zoteroID = translator.translatorID;
 
-				listcell = document.createElement("listcell");
-				listcell.setAttribute("label", translator.label);
+				listcell = document.createXULElement("hbox");
+				listcell.setAttribute('flex', '1');
+				listcell.append(translator.label);
 				listitem.appendChild(listcell);
-				listcell = document.createElement("listcell");
-				listcell.setAttribute("label", translator.creator);
+				listcell = document.createXULElement("hbox");
+				listcell.setAttribute('width', '130');
+				listcell.append(translator.creator);
 				listitem.appendChild(listcell);
 
 				listbox.appendChild(listitem);
 			}
 		}
-	});
+	};
 	
 	this.accept = function () {
-		var translatorID = document.getElementById("listbox").selectedItem.getUserData("zotero-id");
+		var translatorID = document.getElementById("listbox").selectedItem.dataset.zoteroID;
 		var translator = window.arguments[0].translatorProvider.get(translatorID);
 		
 		Zotero.debug(translatorID);
diff --git a/chrome/content/scaffold/load.xul b/chrome/content/scaffold/load.xhtml
similarity index 70%
rename from chrome/content/scaffold/load.xul
rename to chrome/content/scaffold/load.xhtml
index 4f7a213662..e768639276 100644
--- a/chrome/content/scaffold/load.xul
+++ b/chrome/content/scaffold/load.xhtml
@@ -25,24 +25,23 @@
 -->
 <?xml-stylesheet href="chrome://global/skin/" type="text/css"?>
 <?xml-stylesheet href="chrome://scaffold/skin/scaffold.css" type="text/css"?>
+<?xml-stylesheet href="chrome://zotero/skin/zotero.css" type="text/css"?>
 
 <!DOCTYPE window SYSTEM "chrome://scaffold/locale/scaffold.dtd">
-<dialog xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
-	title="&scaffold.load.title;" width="400" height="330" buttons="cancel,accept"
-	ondialogaccept="Scaffold_Load.accept()" onload="Scaffold_Load.onLoad()"
+<window
+    xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+    title="&scaffold.load.title;" width="400" height="330"
+    onload="Scaffold_Load.onLoad()">
+<dialog buttons="cancel,accept"
 	id="scaffold-load">
 	
 	<script src="chrome://zotero/content/include.js"/>
 	<script src="load.js"/>
 	
-	<listbox id="listbox" flex="1">
-		<listhead>
-			<listheader label="&scaffold.load.label.label;"/>
-			<listheader label="&scaffold.load.creator.label;"/>
-		</listhead>
-		<listcols>
-			<listcol flex="1"/>
-			<listcol width="130"/>
-		</listcols>
-	</listbox>
+    <listheader>
+        <treecol flex="1" label="&scaffold.load.label.label;"/>
+		<treecol width="130" label="&scaffold.load.creator.label;"/>
+    </listheader>
+	<richlistbox id="listbox" flex="1"/>
 </dialog>
+</window>
diff --git a/chrome/content/scaffold/scaffold.js b/chrome/content/scaffold/scaffold.js
index 1f80f4b660..14e0b3ee37 100644
--- a/chrome/content/scaffold/scaffold.js
+++ b/chrome/content/scaffold/scaffold.js
@@ -23,7 +23,9 @@
     ***** END LICENSE BLOCK *****
 */
 
-Components.utils.import("resource://gre/modules/Services.jsm");
+var { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
+var { E10SUtils } = ChromeUtils.import("resource://gre/modules/E10SUtils.jsm");
+
 import FilePicker from 'zotero/modules/filePicker';
 
 var Zotero = Components.classes["@zotero.org/Zotero;1"]
@@ -53,10 +55,12 @@ function fix2028(str) {
 }
 
 var Scaffold = new function () {
-	var _browser, _frames, _document;
+	var _browser, _frames = [], _document;
 	var _translatorsLoadedPromise;
 	var _translatorProvider = null;
 	var _lastModifiedTime = 0;
+
+	this.browser = () => _browser;
 	
 	var _editors = {};
 
@@ -85,17 +89,19 @@ var Scaffold = new function () {
 		
 		_browser = document.getElementById('browser');
 
-		_browser.addEventListener("pageshow",
-			_updateFrames, true);
-		_updateFrames();
+		window.messageManager.addMessageListener('Scaffold:Load', ({ data }) => {
+			document.getElementById("browser-url").value = data.url;
+		});
+
+		window.messageManager.loadFrameScript('chrome://scaffold/content/content.js', true);
 		
 		let browserUrl = document.getElementById("browser-url");
-		browserUrl.addEventListener('keypress', function (e) {
-			if (e.keyCode == e.DOM_VK_RETURN) {
-				_browser.loadURIWithFlags(
-					browserUrl.value,
-					Components.interfaces.nsIWebNavigation.LOAD_FLAGS_BYPASS_CACHE
-				);
+		browserUrl.addEventListener('keydown', function (e) {
+			if (e.key == 'Enter') {
+				Zotero.debug('Scaffold: Loading URL in browser: ' + browserUrl.value);
+				_browser.loadURI(browserUrl.value, {
+					triggeringPrincipal: Services.scriptSecurityManager.getSystemPrincipal()
+				});
 			}
 		});
 				
@@ -107,6 +113,8 @@ var Scaffold = new function () {
 		if (size) {
 			this.setFontSize(size);
 		}
+
+		document.getElementById('tabpanels').addEventListener('select', event => Scaffold.handleTabSelect(event));
 		
 		this.generateTranslatorID();
 		
@@ -570,9 +578,8 @@ var Scaffold = new function () {
 		if (translatorID === undefined) {
 			var io = {};
 			io.translatorProvider = _translatorProvider;
-			io.url = _getDocument()?.location.href || 'about:blank';
-			io.rootUrl = _browser.contentDocument.location.href;
-			window.openDialog("chrome://scaffold/content/load.xul",
+			io.url = io.rootUrl = _browser.currentURI.spec;
+			window.openDialog("chrome://scaffold/content/load.xhtml",
 				"_blank", "chrome,modal", io);
 			translator = io.dataOut;
 		}
@@ -752,8 +759,12 @@ var Scaffold = new function () {
 	};
 
 	this.handleTabSelect = function (event) {
+		if (event.target.tagName != 'tabpanels') {
+			return;
+		}
+
 		// Focus editor when switching to tab
-		var tab = event.target.selectedItem.id.match(/^tab-(.+)$/)[1];
+		var tab = document.getElementById('tabs').selectedItem.id.match(/^tab-(.+)$/)[1];
 		switch (tab) {
 			case 'import':
 			case 'code':
@@ -785,7 +796,7 @@ var Scaffold = new function () {
 
 		let editImport = document.getElementById('testing_editImport');
 		let openURL = document.getElementById('testing_openURL');
-		if (selected.getUserData('test-type') == 'web') {
+		if (selected.dataset.testType == 'web') {
 			editImport.setAttribute('disabled', true);
 			openURL.removeAttribute('disabled');
 		}
@@ -864,7 +875,7 @@ var Scaffold = new function () {
 		// Handle generic call run('detect'), run('do')
 		if (functionToRun == "detect" || functionToRun == "do") {
 			if (document.getElementById('checkbox-web').checked
-				&& _browser.contentWindow.location.href != 'about:blank') {
+				&& _browser.currentURI.spec != 'about:blank') {
 				functionToRun += 'Web';
 			}
 			else if (document.getElementById('checkbox-import').checked
@@ -887,7 +898,9 @@ var Scaffold = new function () {
 
 		_logOutput(`Running ${functionToRun}`);
 		
-		let input = _getInput(functionToRun);
+		let input = await _getInput(functionToRun);
+		Zotero.debug('got input')
+		Zotero.debug(input)
 
 		if (functionToRun.endsWith('Export')) {
 			let numItems = Zotero.getActiveZoteroPane().getSelectedItems().length;
@@ -991,8 +1004,8 @@ var Scaffold = new function () {
 	/**
 	 * Test target regular expression against document URL and log the result
 	 */
-	this.logTargetRegex = function () {
-		_logOutput(_testTargetRegex(_getDocument()));
+	this.logTargetRegex = async function () {
+		_logOutput(_testTargetRegex(await _getDocument()));
 	};
 	
 	/**
@@ -1016,7 +1029,7 @@ var Scaffold = new function () {
 	 */
 	function _selectItems(obj, itemList) {
 		var io = { dataIn: itemList, dataOut: null };
-		window.openDialog("chrome://zotero/content/ingester/selectitems.xul",
+		window.openDialog("chrome://zotero/content/ingester/selectitems.xhtml",
 			"_blank", "chrome,modal,centerscreen,resizable=yes", io);
 
 		return io.dataOut;
@@ -1103,7 +1116,7 @@ var Scaffold = new function () {
 				+ ":" + Zotero.Utilities.lpad(date.getSeconds(), '0', 2)
 				+ " " + string.replace(/\n/g, "\n         ");
 		// move to end
-		output.inputField.scrollTop = output.inputField.scrollHeight;
+		output.scrollTop = output.scrollHeight;
 	}
 
 	/*
@@ -1131,7 +1144,7 @@ var Scaffold = new function () {
 	/*
 	 * gets appropriate input for the given type/method
 	 */
-	function _getInput(typeOrMethod) {
+	async function _getInput(typeOrMethod) {
 		typeOrMethod = typeOrMethod.toLowerCase();
 		if (typeOrMethod.endsWith('web')) {
 			return _getDocument();
@@ -1572,7 +1585,7 @@ var Scaffold = new function () {
 			return Promise.reject(new Error(`Test of type export cannot be created`));
 		}
 
-		let input = _getInput(type);
+		let input = await _getInput(type);
 
 		if (type == "web") {
 			let tester = new Zotero_TranslatorTester(
@@ -1614,6 +1627,14 @@ var Scaffold = new function () {
 	 * populate tests pane and url options in browser pane
 	 */
 	this.populateTests = function () {
+		function wrapWithHBox(elem, { flex = undefined, width = undefined } = {}) {
+			let hbox = document.createXULElement('hbox');
+			hbox.append(elem);
+			hbox.setAttribute('flex', flex);
+			hbox.setAttribute('width', width);
+			return hbox;
+		}
+
 		let tests = _loadTestsFromPane();
 		let validateTestsBroadcaster = document.getElementById('validate-tests');
 		if (tests === null) {
@@ -1626,7 +1647,7 @@ var Scaffold = new function () {
 
 		let browserURL = document.getElementById("browser-url");
 		let currentURL = browserURL.value;
-		browserURL.removeAllItems();
+		// browserURL.removeAllItems();
 		browserURL.value = currentURL;
 
 		let listBox = document.getElementById("testing-listbox");
@@ -1634,8 +1655,8 @@ var Scaffold = new function () {
 		let oldStatuses = {};
 		for (let i = 0; i < count; i++) {
 			let item = listBox.getItemAtIndex(i);
-			let [, statusCell] = item.getElementsByTagName('listcell');
-			oldStatuses[item.getUserData('test-string')] = statusCell.getAttribute('label');
+			let [, statusCell] = item.firstElementChild.children;
+			oldStatuses[item.dataset.testString] = statusCell.getAttribute('value');
 		}
 
 		let testIndex = 0;
@@ -1645,40 +1666,46 @@ var Scaffold = new function () {
 			// try to reuse old rows
 			let item = testIndex < count
 				? listBox.getItemAtIndex(testIndex)
-				: document.createElement('listitem');
+				: document.createXULElement('richlistitem');
 
 			item.innerHTML = ''; // clear children/content if reusing
 
-			let input = document.createElement('listcell');
-			input.setAttribute('label', getTestLabel(test));
-			item.appendChild(input);
+			let hbox = document.createXULElement('hbox');
+			hbox.setAttribute('flex', 1);
+			hbox.setAttribute('align', 'center');
 
-			let status = document.createElement('listcell');
-			status.setAttribute('label', oldStatuses[testString] || 'Not run');
-			item.appendChild(status);
+			let input = document.createXULElement('label');
+			input.value = getTestLabel(test);
+			hbox.appendChild(wrapWithHBox(input, { flex: 1 }));
 
-			let defer = document.createElement('listcell');
-			defer.setAttribute('type', 'checkbox');
-			defer.setAttribute('checked', test.defer);
-			item.appendChild(defer);
+			let status = document.createXULElement('label');
+			status.value = oldStatuses[testString] || 'Not run';
+			hbox.appendChild(wrapWithHBox(status, { width: 150 }));
 
-			item.setUserData('test-string', testString, null);
-			item.setUserData('test-type', test.type);
+			let defer = document.createXULElement('checkbox');
+			defer.checked = test.defer;
+			defer.disabled = true;
+			hbox.appendChild(wrapWithHBox(defer));
+
+			item.appendChild(hbox);
+
+			item.dataset.testString = testString;
+			item.dataset.testType = test.type;
 
 			if (testIndex >= count) {
 				listBox.appendChild(item);
 			}
 
-			if (test.type == 'web') {
-				browserURL.appendItem(test.url);
-			}
+			// if (test.type == 'web') {
+			// 	browserURL.appendItem(test.url);
+			// }
 
 			testIndex++;
 		}
 
 		// remove old rows that we didn't reuse
 		while (listBox.getItemAtIndex(testIndex)) {
-			listBox.removeItemAt(testIndex);
+			listBox.getItemAtIndex(testIndex).remove();
 		}
 	};
 
@@ -1703,7 +1730,7 @@ var Scaffold = new function () {
 	this.editImportFromTest = function () {
 		var listbox = document.getElementById("testing-listbox");
 		var item = listbox.selectedItems[0];
-		var test = JSON.parse(item.getUserData("test-string"));
+		var test = JSON.parse(item.dataset.testString);
 		if (test.input === undefined) {
 			_logOutput("Can't edit input of a non-import/search test.");
 		}
@@ -1726,8 +1753,8 @@ var Scaffold = new function () {
 	this.copyToClipboard = function () {
 		var listbox = document.getElementById("testing-listbox");
 		var item = listbox.selectedItems[0];
-		var url = item.getElementsByTagName("listcell")[0].getAttribute("label");
-		var test = JSON.parse(item.getUserData("test-string"));
+		var url = item.getElementsByTagName("label")[0].getAttribute("value");
+		var test = JSON.parse(item.dataset.testString);
 		var urlOrData = (test.input !== undefined) ? test.input : url;
 		Zotero.Utilities.Internal.copyTextToClipboard(urlOrData);
 	};
@@ -1740,15 +1767,14 @@ var Scaffold = new function () {
 	this.openURL = function (openExternally) {
 		var listbox = document.getElementById("testing-listbox");
 		var item = listbox.selectedItems[0];
-		var url = item.getElementsByTagName("listcell")[0].getAttribute("label");
+		var url = item.getElementsByTagName("label")[0].getAttribute("value");
 		if (openExternally) {
 			Zotero.launchURL(url);
 		}
 		else {
-			_browser.loadURIWithFlags(
-				url,
-				Components.interfaces.nsIWebNavigation.LOAD_FLAGS_BYPASS_CACHE
-			);
+			_browser.loadURI(url, {
+				triggeringPrincipal: Services.scriptSecurityManager.getSystemPrincipal()
+			});
 			_showTab('browser');
 		}
 	};
@@ -1792,14 +1818,14 @@ var Scaffold = new function () {
 		if (!items || items.length == 0) return; // No action if nothing selected
 		var tests = [];
 		for (let item of items) {
-			item.getElementsByTagName("listcell")[1].setAttribute("label", "Running");
-			var test = JSON.parse(item.getUserData("test-string"));
+			item.getElementsByTagName("label")[1].setAttribute("value", "Running");
+			var test = JSON.parse(item.dataset.testString);
 			test["ui-item"] = item;
 			tests.push(test);
 		}
 
 		this.runTests(tests, (obj, test, status, message) => {
-			test["ui-item"].getElementsByTagName("listcell")[1].setAttribute("label", message);
+			test["ui-item"].getElementsByTagName("label")[1].setAttribute("value", message);
 		});
 	};
 
@@ -1823,8 +1849,8 @@ var Scaffold = new function () {
 		var itemIndices = items.map(item => listbox.getIndexOfItem(item));
 		var tests = [];
 		for (let item of items) {
-			item.getElementsByTagName("listcell")[1].setAttribute("label", "Updating");
-			var test = JSON.parse(item.getUserData("test-string"));
+			item.getElementsByTagName("label")[1].setAttribute("value", "Updating");
+			var test = JSON.parse(item.dataset.testString);
 			tests.push(test);
 		}
 
@@ -1835,13 +1861,13 @@ var Scaffold = new function () {
 				// Assume sequential. TODO: handle this properly via test ID of some sort
 				if (newTest) {
 					message = "Test updated";
-					items[testsDone].setUserData("test-string", _stringifyTests(newTest, 1));
+					items[testsDone].dataset.testString = _stringifyTests(newTest, 1);
 					tests[testsDone] = newTest;
 				}
 				else {
 					message = "Update failed";
 				}
-				items[testsDone].getElementsByTagName("listcell")[1].setAttribute("label", message);
+				items[testsDone].getElementsByTagName("label")[1].setAttribute("value", message);
 				testsDone++;
 			});
 
@@ -2011,77 +2037,19 @@ var Scaffold = new function () {
 		return guid;
 	}
 
-	/*
-	 * updates list of available frames and show URL of active tab
-	 */
-	function _updateFrames() {
-		var doc = _browser.contentDocument;
-		
-		// Show URL of active tab
-		document.getElementById("browser-url").value = doc.location.href;
-		
-		// No need to run if Scaffold isn't open
-		var menulist = _document.getElementById("menulist-testFrame");
-		if (!_document || !menulist) return;
-
-		menulist.removeAllItems();
-		var popup = _document.createElement("menupopup");
-		menulist.appendChild(popup);
-
-		_frames = [];
-
-		var frames = doc.getElementsByTagName("frame");
-		if (frames.length) {
-			_getFrames(frames, popup);
-		}
-		else {
-			var item = _document.createElement("menuitem");
-			item.setAttribute("label", "Default");
-			popup.appendChild(item);
-
-			_frames = [doc];
-		}
-
-		menulist.selectedIndex = 0;
-	}
-
-	/*
-	 * recursively searches for frames
-	 */
-	function _getFrames(frames, popup) {
-		for (var i = 0; i < frames.length; i++) {
-			var frame = frames[i];
-			if (frame.contentDocument) {
-				// get a good name
-				var frameName;
-				if (frame.title) {
-					frameName = frame.title;
-				}
-				else if (frame.name) {
-					frameName = frame.name;
-				}
-				else {
-					frameName = frame.contentDocument.location.href;
-				}
-
-				// add frame
-				var item = _document.createElement("menuitem");
-				item.setAttribute("label", frameName);
-				popup.appendChild(item);
-				_frames.push(frame.contentDocument);
-
-				// see if frame has its own frames
-				var subframes = frame.contentDocument.getElementsByTagName("frame");
-				if (subframes.length) _getFrames(subframes, popup);
-			}
-		}
-	}
-
 	/*
 	 * gets selected frame/document
 	 */
 	function _getDocument() {
-		return _frames[_document.getElementById("menulist-testFrame").selectedIndex];
+		return new Promise((resolve) => {
+			window.messageManager.addMessageListener('Scaffold:Document', function onDocument({ data }) {
+				window.messageManager.removeMessageListener('Scaffold:Document', onDocument);
+				let doc = new DOMParser().parseFromString(data.html, 'text/html');
+				doc = Zotero.HTTP.wrapDocument(doc, data.url);
+				resolve(doc);
+			});
+			window.messageManager.broadcastAsyncMessage('Scaffold:GetDocument');
+		});
 	}
 	
 	function _getDocumentURL(doc) {
diff --git a/chrome/content/scaffold/scaffold.xul b/chrome/content/scaffold/scaffold.xhtml
similarity index 58%
rename from chrome/content/scaffold/scaffold.xul
rename to chrome/content/scaffold/scaffold.xhtml
index b95a3db499..cf98aaf64f 100644
--- a/chrome/content/scaffold/scaffold.xul
+++ b/chrome/content/scaffold/scaffold.xhtml
@@ -30,10 +30,6 @@
 <?xml-stylesheet href="chrome://zotero-platform-version/content/style.css"?>
 <?xml-stylesheet href="chrome://zotero-platform/content/zotero-react-client.css"?>
 
-<?xul-overlay href="chrome://zotero/content/containers/containers.xul"?>
-<?xul-overlay href="chrome://zotero/content/standalone/editMenuOverlay.xul"?>
-<?xul-overlay href="chrome://zotero-platform/content/standalone/menuOverlay.xul"?>
-
 <!DOCTYPE window [
 	<!ENTITY % globalDTD SYSTEM "chrome://global/locale/global.dtd"> %globalDTD;
 	<!ENTITY % standaloneDTD SYSTEM "chrome://zotero/locale/standalone.dtd" > %standaloneDTD;
@@ -44,15 +40,35 @@
 ]>
 
 <window id="scaffold" width="800" height="600" minheight="600" persist="screenX screenY width height"
- title="Scaffold"
- xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
-	<script src="chrome://zotero/content/include.js"/>
-	<script src="chrome://zotero/content/xpcom/translate/testTranslators/translatorTester.js"/>
-	<script src="translators.js"/>
-	<script src="scaffold.js"/>
+	title="Scaffold"
+	xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+	xmlns:html="http://www.w3.org/1999/xhtml"
+	style="display: flex;">
 
-	<script src="chrome://global/content/globalOverlay.js"/>
-	<script src="chrome://global/content/contentAreaUtils.js"/>
+	<html:link rel="localization" href="zotero/menubar.ftl"/>
+	<html:link rel="localization" href="zotero/textActions.ftl"/>
+
+	<script>
+		var {Services} = ChromeUtils.import("resource://gre/modules/Services.jsm");
+		
+		Services.scriptloader.loadSubScript("chrome://zotero/content/include.js", this);
+		
+		Services.scriptloader.loadSubScript("resource://zotero/require.js", this);
+		Services.scriptloader.loadSubScript("chrome://zotero/content/xpcom/translate/testTranslators/translatorTester.js", this);
+		Services.scriptloader.loadSubScript("chrome://scaffold/content/translators.js", this);
+		Services.scriptloader.loadSubScript("chrome://scaffold/content/scaffold.js", this);
+		
+		// Mozilla scripts
+		Services.scriptloader.loadSubScript("chrome://global/content/globalOverlay.js", this);
+		Services.scriptloader.loadSubScript("chrome://global/content/editMenuOverlay.js", this);
+		Services.scriptloader.loadSubScript("chrome://global/content/contentAreaUtils.js", this);
+		if (Zotero.isMac) {
+			Services.scriptloader.loadSubScript("chrome://global/content/macWindowMenu.js", this);
+		}
+
+		// Custom elements
+		Services.scriptloader.loadSubScript("chrome://global/content/customElements.js", this);
+	</script>
 
 	<commandset id="mainCommandSet">
 		<command id="cmd_quitApplication" oncommand="goQuitApplication(event);"/>
@@ -100,10 +116,38 @@
 		<key modifiers="accel" key="9" oncommand="Scaffold.showTabNumbered(9)"/>
 	</keyset>
 
-	<keyset id="editMenuKeys"/>
+	<!--
+    
+    TODO: Customize per platform without ifdef?
+    
+    <keyset id="editMenuKeys">
+		<key id="key_undo" data-l10n-id="text-action-undo-shortcut" modifiers="accel" command="cmd_undo"/>
+		<key id="key_redo"
+		
+#ifdef XP_UNIX
+			data-l10n-id="text-action-undo-shortcut"
+			modifiers="accel,shift"
+#else
+			data-l10n-id="text-action-redo-shortcut"
+			modifiers="accel"
+#endif
+			command="cmd_redo"/>
+		<key id="key_cut" data-l10n-id="text-action-cut-shortcut" modifiers="accel" command="cmd_cut"/>
+		<key id="key_copy" data-l10n-id="text-action-copy-shortcut" modifiers="accel" command="cmd_copy"/>
+		<key id="key_paste" data-l10n-id="text-action-paste-shortcut" modifiers="accel" command="cmd_paste"/>
+		<key id="key_delete" keycode="VK_DELETE" command="cmd_delete"/>
+		<key id="key_selectAll" data-l10n-id="text-action-select-all-shortcut" modifiers="accel" command="cmd_selectAll"/>
+		<key id="key_find" key="&findCmd.key;" modifiers="accel" command="cmd_find"/>
+		<key id="key_findAgain" key="&findAgainCmd.key;" modifiers="accel" command="cmd_findAgain"/>
+		<key id="key_findPrevious" key="&findAgainCmd.key;" modifiers="shift,accel" command="cmd_findPrevious"/>
+		<key id="key_findAgain2" keycode="&findAgainCmd.key2;" command="cmd_findAgain"/>
+		<key id="key_findPrevious2" keycode="&findAgainCmd.key2;" modifiers="shift" command="cmd_findPrevious"/>
+	</keyset>
+  
+	-->
 
 	<popupset>
-		<menupopup id="testing-context-menue">
+		<menupopup id="testing-context-menu">
 			<menuitem label="&scaffold.testing.copyToClipboard;" tooltiptext="Copy the URL or data for the current test to the clipboard" oncommand="Scaffold.copyToClipboard()"/>
 			<menuitem id="testing_editImport" label="&scaffold.testing.edit;" tooltiptext="Edit the input data for the current test" oncommand="Scaffold.editImportFromTest()"/>
 			<menu id="testing_openURL" label="&scaffold.testing.openUrl;">
@@ -139,19 +183,44 @@
 				</menupopup>
 			</menu>
 
-			<menu id="menu_edit">
+			<menu id="menu_edit" data-l10n-id="menu-edit">
 				<menupopup id="menu_EditPopup">
-					<menuitem id="menu_undo" command="cmd_undo"/>
-					<menuitem id="menu_redo" command="cmd_redo"/>
+					<menuitem id="menu_undo"
+							key="key_undo"
+							command="cmd_undo" data-l10n-id="text-action-undo"/>
+					<menuitem id="menu_redo"
+							key="key_redo"
+							command="cmd_redo" data-l10n-id="text-action-redo"/>
 					<menuseparator/>
-					<menuitem id="menu_cut"/>
-					<menuitem id="menu_copy"/>
-					<menuitem id="menu_paste"/>
-					<menuitem id="menu_delete"/>
-					<menuseparator class="menu-type-library"/>
-					<menuitem id="menu_selectAll" class="menu-type-library" command="cmd_selectAll"/>
-					<menuseparator class="menu-type-library"/>
-					<menuitem id="menu_find" class="menu-type-library" command="cmd_find"/>
+					<menuitem id="menu_cut"
+							key="key_cut"
+							command="cmd_cut" data-l10n-id="text-action-cut"/>
+					<menuitem id="menu_copy"
+							key="key_copy"
+							command="cmd_copy" data-l10n-id="text-action-copy"/>
+					<menuitem id="menu_paste"
+							key="key_paste"
+							command="cmd_paste" data-l10n-id="text-action-paste"/>
+					<menuitem id="menu_delete"
+							key="key_delete"
+							command="cmd_delete" data-l10n-id="text-action-delete"/>
+					<menuseparator/>
+					<menuitem id="menu_selectAll"
+							key="key_selectAll"
+							command="cmd_selectAll" data-l10n-id="text-action-select-all"/>
+					<menuseparator/>
+					<menuitem id="menu_find" label="&findCmd.label;"
+							key="key_find" accesskey="&findCmd.accesskey;"
+							command="cmd_find"/>
+					<!--
+					#ifdef XP_UNIX
+					#ifndef XP_MACOSX
+					<menuseparator/>
+					<menuitem id="menu_preferences"
+						oncommand="Zotero.Utilities.Internal.openPreferences()" data-l10n-id="menu-preferences"/>
+					#endif
+					#endif
+					-->
 				</menupopup>
 			</menu>
 
@@ -197,11 +266,87 @@
 				</menupopup>
 			</menu>
 
+			<!-- ifdef mac -->
+			<commandset id="macCommandSet"> <!-- was mainCommandSet -->
+				<command id="minimizeWindow"
+						label="&minimizeWindow.label;"
+						oncommand="window.minimize();" />
+				<command id="zoomWindow"
+						label="&zoomWindow.label;"
+						oncommand="zoomWindow();" />
+			</commandset>
+
+			<keyset id="macKeyset">  <!-- was mainKeySet -->
+				<key id="key_minimizeWindow"
+						command="minimizeWindow"
+						key="&minimizeWindow.key;"
+						modifiers="accel"/>
+				
+				<!-- These are used to build the Application menu under Cocoa widgets -->
+				<key id="key_preferencesCmdMac"
+						key="&preferencesCmdMac.commandkey;"
+						modifiers="accel"/>
+				<key id="key_hideThisAppCmdMac"
+						key="&hideThisAppCmdMac.commandkey;"
+						modifiers="accel"/>
+				<key id="key_hideOtherAppsCmdMac"
+						key="&hideOtherAppsCmdMac.commandkey;"
+						modifiers="accel,alt"/>
+				<key id="key_quitApplication"
+						key="&quitApplicationCmdMac.key;"
+						command="cmd_quitApplication"
+						modifiers="accel"/>
+			</keyset>
+
+			<!-- nsMenuBarX hides these and uses them to build the Application menu. -->
+			<menupopup id="menu_FilePopup">
+				<menuitem id="menu_preferences"
+						label="&preferencesCmdMac.label;"
+						key="key_preferencesCmdMac"
+						oncommand="Zotero.Utilities.Internal.openPreferences()"/>
+				<menuitem id="menu_mac_services"
+						label="&servicesMenuMac.label;"/>
+				<menuitem id="menu_mac_hide_app"
+						label="&hideThisAppCmdMac.label;"
+						key="key_hideThisAppCmdMac"/>
+				<menuitem id="menu_mac_hide_others"
+						label="&hideOtherAppsCmdMac.label;"
+						key="key_hideOtherAppsCmdMac"/>
+				<menuitem id="menu_mac_show_all"
+						label="&showAllAppsCmdMac.label;"/>
+				<menuitem id="menu_FileQuitItem"
+						label="&quitApplicationCmdMac.label;"
+						key="key_quitApplication"
+						command="cmd_quitApplication"/>
+			</menupopup>
+
 			<menu id="windowMenu"
-				  label="&windowMenu.label;"
-				  onpopupshowing="macWindowMenuDidShow();"
-				  onpopuphidden="macWindowMenuDidHide();">
+					label="&windowMenu.label;"
+					datasources="rdf:window-mediator" ref="NC:WindowMediatorRoot"
+					onpopupshowing="macWindowMenuDidShow();"
+					onpopuphidden="macWindowMenuDidHide();"
+					hidden="false">
+				<template>
+					<rule>
+						<menupopup>
+							<menuitem uri="rdf:*"
+									label="rdf:http://home.netscape.com/NC-rdf#Name"
+									type="radio"
+									name="windowList"
+									oncommand="ShowWindowFromResource(event.target)"/>
+						</menupopup>
+					</rule>
+				</template>
+				<menupopup id="windowPopup">
+					<menuitem command="minimizeWindow" label="&minimizeWindow.label;" key="key_minimizeWindow"/>
+					<menuitem command="zoomWindow" label="&zoomWindow.label;"/>
+					<!-- decomment when "BringAllToFront" is implemented
+						<menuseparator/>
+						<menuitem label="&bringAllToFront.label;" disabled="true"/> -->
+					<menuseparator id="sep-window-list"/>
+				</menupopup>
 			</menu>
+			<!-- endif -->
 
 			<menu id="helpMenu" label="&helpMenu.label;" accesskey="&helpMenu.accesskey;">
 				<menupopup id="mb-help-popup">
@@ -251,88 +396,61 @@
 		</toolbar>
 		<hbox flex="1">
 			<tabbox id="left-tabbox" flex="2" width="300">
-				<tabs id="tabs" onselect="Scaffold.handleTabSelect(event)">
+				<tabs id="tabs">
 					<tab id="tab-metadata" label="&scaffold.tabs.metadata.label;"/>
 					<tab id="tab-code" label="&scaffold.tabs.code.label;"/>
 					<tab id="tab-tests" label="&scaffold.tabs.tests.label;"/>
 					<tab id="tab-browser" label="Browser"/>
 					<tab id="tab-import" label="&scaffold.tabs.import.label;"/>
 				</tabs>
-				<tabpanels flex="1">
+				<tabpanels flex="1" id="tabpanels">
 					<tabpanel flex="1" id="tabpanel-metadata">
-						<grid flex="1">
-							<columns>
-								<column/>
-								<column flex="1"/>
-							</columns>
+						<html:div id="metadata-grid">
+							<label class="label-metadata" value="&scaffold.metadata.translatorID.label;" control="textbox-translatorID"/>
+							<html:div class="button-row">
+								<html:input type="text" id="textbox-translatorID"/>
+								<button label="&scaffold.metadata.translatorID.generate;" oncommand="Scaffold.generateTranslatorID()"/>
+							</html:div>
 
-							<rows>
-								<row align="center">
-									<label class="label-metadata" value="&scaffold.metadata.translatorID.label;" control="textbox-translatorID"/>
-									<hbox>
-										<textbox id="textbox-translatorID" flex="1"/>
-										<button label="&scaffold.metadata.translatorID.generate;" oncommand="Scaffold.generateTranslatorID()"/>
-									</hbox>
-								</row>
+							<label class="label-metadata" value="&scaffold.metadata.label.label;" control="textbox-label"/>
+							<html:input type="text" id="textbox-label" flex="1" value="&scaffold.metadata.label.default;"/>
 
-								<row align="center">
-									<label class="label-metadata" value="&scaffold.metadata.label.label;" control="textbox-label"/>
-									<textbox id="textbox-label" flex="1" value="&scaffold.metadata.label.default;"/>
-								</row>
+							<label class="label-metadata" value="&scaffold.metadata.creator.label;" control="textbox-creator"/>
+							<html:input type="text" id="textbox-creator" flex="1"/>
 
-								<row align="center">
-									<label class="label-metadata" value="&scaffold.metadata.creator.label;" control="textbox-creator"/>
-									<textbox id="textbox-creator" flex="1"/>
-								</row>
+							<label class="label-metadata" value="&scaffold.metadata.target.label;" control="textbox-target"/>
+							<html:div class="button-row">
+								<html:input type="text" id="textbox-target" flex="1"/>
+								<button label="&scaffold.metadata.target.testRegex;" oncommand="Scaffold.logTargetRegex()"/>
+							</html:div>
 
-								<row align="center">
-									<label class="label-metadata" value="&scaffold.metadata.target.label;" control="textbox-target"/>
-									<hbox>
-										<textbox id="textbox-target" flex="1"/>
-										<button label="&scaffold.metadata.target.testRegex;" oncommand="Scaffold.logTargetRegex()"/>
-									</hbox>
-								</row>
+							<label class="label-metadata" value="&scaffold.metadata.targetAll.label;" control="textbox-target-all" style="display: none"/>
+							<html:input type="text" id="textbox-target-all" flex="1" style="display: none"/>
 
-								<row align="center">
-									<label class="label-metadata" value="&scaffold.metadata.targetAll.label;" control="textbox-target-all" style="display: none"/>
-									<textbox id="textbox-target-all" flex="1" style="display: none"/>
-								</row>
+							<label class="label-metadata" value="&scaffold.metadata.configOptions.label;" control="textbox-configOptions"/>
+							<html:input type="text" id="textbox-configOptions" flex="1"/>
 
-								<row align="center">
-									<label class="label-metadata" value="&scaffold.metadata.configOptions.label;" control="textbox-configOptions"/>
-									<textbox id="textbox-configOptions" flex="1"/>
-								</row>
+							<label class="label-metadata" value="&scaffold.metadata.displayOptions.label;" control="textbox-displayOptions"/>
+							<html:input type="text" id="textbox-displayOptions" flex="1"/>
 
-								<row align="center">
-									<label class="label-metadata" value="&scaffold.metadata.displayOptions.label;" control="textbox-displayOptions"/>
-									<textbox id="textbox-displayOptions" flex="1"/>
-								</row>
+							<label class="label-metadata" value="&scaffold.metadata.minVersion.label;" control="textbox-minVersion"/>
+							<html:div>
+								<html:input type="text" id="textbox-minVersion" flex="1" value="5.0"/>
+								<label class="label-metadata" value="&scaffold.metadata.priority.label;" control="textbox-priority"/>
+								<html:input type="text" id="textbox-priority" flex="1" value="&scaffold.metadata.priority.default;"/>
+							</html:div>
 
-								<row align="center">
-									<label class="label-metadata" value="&scaffold.metadata.minVersion.label;" control="textbox-minVersion"/>
-									<hbox>
-										<textbox id="textbox-minVersion" flex="1" value="5.0"/>
-										<label class="label-metadata" value="&scaffold.metadata.priority.label;" control="textbox-priority"/>
-										<textbox id="textbox-priority" flex="1" value="&scaffold.metadata.priority.default;"/>
-									</hbox>
-								</row>
+							<label class="label-metadata" value="&scaffold.metadata.hiddenPrefs.label;" control="textbox-hidden-prefs" style="display: none"/>
+							<html:input type="text" id="textbox-hidden-prefs" flex="1" style="display: none"/>
 
-								<row align="center">
-									<label class="label-metadata" value="&scaffold.metadata.hiddenPrefs.label;" control="textbox-hidden-prefs" style="display: none"/>
-									<textbox id="textbox-hidden-prefs" flex="1" style="display: none"/>
-								</row>
-
-								<row align="center">
-									<label class="label-metadata" value="&scaffold.metadata.translatorType.label;"/>
-									<hbox id="checkboxes-translatorType">
-										<checkbox id="checkbox-import" label="&scaffold.metadata.translatorType.import;"/>
-										<checkbox id="checkbox-export" label="&scaffold.metadata.translatorType.export;"/>
-										<checkbox id="checkbox-web" label="&scaffold.metadata.translatorType.web;" checked="true"/>
-										<checkbox id="checkbox-search" label="&scaffold.metadata.translatorType.search;"/>
-									</hbox>
-								</row>
-							</rows>
-						</grid>
+							<label class="label-metadata" value="&scaffold.metadata.translatorType.label;"/>
+							<html:div id="checkboxes-translatorType">
+								<checkbox id="checkbox-import" label="&scaffold.metadata.translatorType.import;"/>
+								<checkbox id="checkbox-export" label="&scaffold.metadata.translatorType.export;"/>
+								<checkbox id="checkbox-web" label="&scaffold.metadata.translatorType.web;" checked="true"/>
+								<checkbox id="checkbox-search" label="&scaffold.metadata.translatorType.search;"/>
+							</html:div>
+						</html:div>
 					</tabpanel>
 					<tabpanel flex="1" id="tabpanel-code">
 						<vbox flex="1">
@@ -342,24 +460,24 @@
 					<tabpanel flex="1" id="tabpanel-tests">
 						<vbox flex="1">
 							<vbox flex="1">
-								<hbox flex="1" context="testing-context-menue">
-									<keyset>
-										<key id="key-delete-tests" observes="validate-tests" keycode="VK_BACK" oncommand="Scaffold.deleteSelectedTests()"/>
-									</keyset>
+								<keyset>
+									<key id="key-delete-tests" observes="validate-tests" keycode="VK_BACK" oncommand="Scaffold.deleteSelectedTests()"/>
+								</keyset>
 
-									<listbox id="testing-listbox" observes="validate-tests" flex="1" seltype="multiple" onselect="Scaffold.handleTestSelect(event)">
-										<listhead>
-											<listheader label="&scaffold.testing.input.label;"/>
-											<listheader label="&scaffold.testing.status.label;"/>
-											<listheader label="&scaffold.testing.defer.label;"/>
-										</listhead>
-										<listcols>
-											<listcol flex="1"/>
-											<listcol class="listcol-testMessage"/>
-											<listcol/>
-										</listcols>
-									</listbox>
-								</hbox>
+								<listheader>
+									<treecol label="&scaffold.testing.input.label;" flex="1"/>
+									<treecol label="&scaffold.testing.status.label;" width="150"/>
+									<treecol label="&scaffold.testing.defer.label;"/>
+								</listheader>
+								<richlistbox
+									id="testing-listbox"
+									class="theme-listbox"
+									observes="validate-tests"
+									flex="1"
+									seltype="multiple"
+									onselect="Scaffold.handleTestSelect(event)"
+									context="testing-context-menu"
+								/>
 								<hbox>
 									<button observes="validate-tests" label="&scaffold.testing.delete;" tooltiptext="Delete the selected tests" oncommand="Scaffold.deleteSelectedTests()"/>
 									<button observes="validate-tests" label="&scaffold.testing.run;" tooltiptext="Run the selected tests" oncommand="Scaffold.runSelectedTests()"/>
@@ -374,13 +492,18 @@
 						<vbox flex="1">
 							<hbox align="center">
 								<label control="textbox-tabUrl" value="&scaffold.tabUrl.label;"/>
-								<menulist id="browser-url" editable="true" flex="1">
-									<menupopup></menupopup>
-								</menulist>
+								<html:input id="browser-url" style="-moz-box-flex: 1;"/>
 								<button observes="validate-tests" label="&scaffold.testing.create.web;" tooltiptext="Create a new test from the current page" oncommand="Scaffold.saveTestFromCurrent('web')"/>
 							</hbox>
 							
-							<browser id="browser" src="about:blank" type="content" flex="1"></browser>
+							<browser
+								id="browser"
+								type="content"
+								remote="false"
+								disablehistory="true"
+								src="about:blank"
+								maychangeremoteness="true"
+								flex="1"/>
 						</vbox>
 					</tabpanel>
 					<tabpanel flex="1" id="tabpanel-import">
@@ -397,13 +520,7 @@
 			<splitter resizeafter="farthest" />
 
 			<vbox id="right-pane" flex="1">
-				
-				<hbox id="hbox-testFrame" width="300">
-					<label control="menulist-testFrame" id="label-testFrame" value="&scaffold.testFrame.label;"/>
-					<menulist id="menulist-testFrame"/>
-				</hbox>
-				
-				<textbox flex="1" id="output" multiline="true" readonly="true"/>
+				<html:textarea style="-moz-box-flex: 1" id="output" readonly="true"/>
 			</vbox>
 		</hbox>
 
diff --git a/chrome/content/zotero/ingester/selectitems.js b/chrome/content/zotero/ingester/selectitems.js
index 52fe496514..efdc762fcb 100644
--- a/chrome/content/zotero/ingester/selectitems.js
+++ b/chrome/content/zotero/ingester/selectitems.js
@@ -26,7 +26,7 @@
 /**
  * @namespace Singleton to interface with the browser when ingesting data
  */
-var Zotero_Ingester_Interface_SelectItems = function() {}
+var Zotero_Ingester_Interface_SelectItems = function () {};
 
 //////////////////////////////////////////////////////////////////////////////
 //
@@ -38,7 +38,10 @@ var Zotero_Ingester_Interface_SelectItems = function() {}
  * Presents items to select in the select box. Assumes window.arguments[0].dataIn is an object with
  * URLs as keys and descriptions as values
  */
-Zotero_Ingester_Interface_SelectItems.init = function() {
+Zotero_Ingester_Interface_SelectItems.init = function () {
+	document.addEventListener('dialogaccept',
+		() => Zotero_Ingester_Interface_SelectItems.acceptSelection());
+
 	// Set font size from pref
 	var sbc = document.getElementById('zotero-select-items-container');
 	Zotero.setFontSize(sbc);
@@ -46,59 +49,66 @@ Zotero_Ingester_Interface_SelectItems.init = function() {
 	this.io = window.arguments[0];
 	var listbox = document.getElementById("zotero-selectitems-links");
 	
-	for(var i in this.io.dataIn) {	// we could use a tree for this if we wanted to
+	for (var i in this.io.dataIn) {	// we could use a tree for this if we wanted to
 		var item = this.io.dataIn[i];
 
 		var title, checked = false;
-		if(item && typeof(item) == "object" && item.title !== undefined) {
+		if (item && typeof item == "object" && item.title !== undefined) {
 			title = item.title;
 			checked = !!item.checked;
-		} else {
+		}
+		else {
 			title = item;
 		}
 
-		var itemNode = document.createElement("listitem");
-		itemNode.setAttribute("type", "checkbox");
+		let itemNode = document.createXULElement("richlistitem");
+		let checkbox = document.createXULElement("checkbox");
+		checkbox.checked = checked;
+		checkbox.label = title;
 		itemNode.setAttribute("value", i);
-		itemNode.setAttribute("label", title);
-		itemNode.setAttribute("checked", checked);
-		listbox.appendChild(itemNode);
+		itemNode.append(checkbox);
+		itemNode.addEventListener('click', (event) => {
+			if (event.target == itemNode) {
+				checkbox.checked = !checkbox.checked;
+			}
+		});
+		listbox.append(itemNode);
 	}
 	
 	// Check item if there is only one
 	if (listbox.itemCount === 1) {
-		listbox.getItemAtIndex(0).setAttribute("checked", true);
+		listbox.getItemAtIndex(0).firstElementChild.checked = true;
 	}
-}
+};
 
 /**
  * Selects or deselects all items
  * @param {Boolean} deselect If true, deselect all items instead of selecting all items
  */
-Zotero_Ingester_Interface_SelectItems.selectAll = function(deselect) {
+Zotero_Ingester_Interface_SelectItems.selectAll = function (deselect) {
 	var listbox = document.getElementById("zotero-selectitems-links");
-	for (var i=0; i<listbox.childNodes.length; i++){
-		listbox.childNodes[i].setAttribute('checked', !deselect);
+	for (var i = 0; i < listbox.childNodes.length; i++) {
+		listbox.childNodes[i].firstElementChild.checked = !deselect;
 	}
-}
+};
 
 /**
  * Called when "OK" button is pressed to populate window.arguments[0].dataOut with selected items
  */
-Zotero_Ingester_Interface_SelectItems.acceptSelection = function() {
+Zotero_Ingester_Interface_SelectItems.acceptSelection = function () {
 	var listbox = document.getElementById("zotero-selectitems-links");
 	
 	var returnObject = false;
-	this.io.dataOut = new Object();
+	this.io.dataOut = {};
 	
 	// collect scrapeURLList from listbox
-	for(var i=0; i<listbox.childNodes.length; i++) {
+	for (var i = 0; i < listbox.childNodes.length; i++) {
 		var itemNode = listbox.childNodes[i];
-		if(itemNode.getAttribute("checked") == "true") {
-			this.io.dataOut[itemNode.getAttribute("value")] = itemNode.getAttribute("label");
+		if (itemNode.firstElementChild.checked) {
+			this.io.dataOut[itemNode.getAttribute("value")] = itemNode.firstElementChild.getAttribute("label");
 			returnObject = true;
 		}
 	}
 	
-	if(!returnObject) this.io.dataOut = null;
-}
\ No newline at end of file
+	if (!returnObject) this.io.dataOut = null;
+};
diff --git a/chrome/content/zotero/ingester/selectitems.xul b/chrome/content/zotero/ingester/selectitems.xhtml
similarity index 72%
rename from chrome/content/zotero/ingester/selectitems.xul
rename to chrome/content/zotero/ingester/selectitems.xhtml
index e22941edc2..2b091a2674 100755
--- a/chrome/content/zotero/ingester/selectitems.xul
+++ b/chrome/content/zotero/ingester/selectitems.xhtml
@@ -25,27 +25,33 @@
 -->
 
 <?xml-stylesheet href="chrome://global/skin/" type="text/css"?>
+<?xml-stylesheet href="chrome://zotero/skin/zotero.css" type="text/css"?>
 <!DOCTYPE window SYSTEM "chrome://zotero/locale/zotero.dtd">
-<dialog xmlns:html="http://www.w3.org/1999/xhtml"
+<window xmlns:html="http://www.w3.org/1999/xhtml"
 	xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
 	title="&zotero.selectitems.title;" width="400" height="330"
 	persist="width height screenX screenY"
-	buttons="cancel,accept"
-	ondialogaccept="Zotero_Ingester_Interface_SelectItems.acceptSelection()"
-	id="zotero-selectitems"
 	onload="Zotero_Ingester_Interface_SelectItems.init()">
-	
-	<script src="../include.js"/>
-	<script src="selectitems.js"/>
+<dialog 
+	buttons="cancel,accept"
+	id="zotero-selectitems">
+
+	<script>
+		var { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
+		Services.scriptloader.loadSubScript("chrome://zotero/content/include.js", this);
+		Services.scriptloader.loadSubScript("chrome://zotero/content/ingester/selectitems.js", this);
+		Services.scriptloader.loadSubScript("chrome://global/content/customElements.js", this);
+	</script>
 	
 	<vbox id="zotero-select-items-container" flex="1">
 		<caption label="&zotero.selectitems.intro.label;" id="zotero-selectitems-intro"/>
 		<box flex="1">
-			<listbox id="zotero-selectitems-links" flex="1" context="zoteroSelectContext"></listbox>
+			<richlistbox id="zotero-selectitems-links" flex="1"></richlistbox>
 		</box>
 		<hbox>
 			<button label="Select All" oncommand="Zotero_Ingester_Interface_SelectItems.selectAll()"/>
 			<button label="Deselect All" oncommand="Zotero_Ingester_Interface_SelectItems.selectAll(true)"/>
 		</hbox>
 	</vbox>
-</dialog>
\ No newline at end of file
+</dialog>
+</window>
diff --git a/chrome/content/zotero/standalone/standalone.js b/chrome/content/zotero/standalone/standalone.js
index 1922f508d9..b0b091f71f 100644
--- a/chrome/content/zotero/standalone/standalone.js
+++ b/chrome/content/zotero/standalone/standalone.js
@@ -912,7 +912,7 @@ function openStyleEditor() {
 
 function openScaffold() {
 	openWindowByType(
-		'chrome://scaffold/content/scaffold.xul',
+		'chrome://scaffold/content/scaffold.xhtml',
 		'zotero:scaffold',
 		'chrome,resizable'
 	);
diff --git a/chrome/content/zotero/xpcom/cookieSandbox.js b/chrome/content/zotero/xpcom/cookieSandbox.js
index 79f34daddf..ba7e151f50 100755
--- a/chrome/content/zotero/xpcom/cookieSandbox.js
+++ b/chrome/content/zotero/xpcom/cookieSandbox.js
@@ -164,7 +164,7 @@ Zotero.CookieSandbox.prototype = {
 	 * @param {nsIInterfaceRequestor} ir
 	 */
 	"attachToInterfaceRequestor": function(ir) {
-		Zotero.CookieSandbox.Observer.trackedInterfaceRequestors.push(Components.utils.getWeakReference(ir.QueryInterface(Components.interfaces.nsIInterfaceRequestor)));
+		Zotero.CookieSandbox.Observer.trackedInterfaceRequestors.push(Cu.getWeakReference(ir.getInterface(Ci.nsIInterfaceRequestor)));
 		Zotero.CookieSandbox.Observer.trackedInterfaceRequestorSandboxes.push(this);
 	},
 	
diff --git a/chrome/skin/default/scaffold/scaffold.css b/chrome/skin/default/scaffold/scaffold.css
index 3ce1c75c16..1c1cf58b0a 100644
--- a/chrome/skin/default/scaffold/scaffold.css
+++ b/chrome/skin/default/scaffold/scaffold.css
@@ -1,6 +1,3 @@
-@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
-@namespace html url("http://www.w3.org/1999/xhtml");
-
 #tb-new {
 	list-style-image: url('chrome://scaffold/skin/new.png');
 }
@@ -53,11 +50,28 @@
 	list-style-image: url('chrome://scaffold/skin/add.png');
 }
 
-#tabpanel-metadata textbox {
-	height:2em;
+#metadata-grid {
+	-moz-box-flex: 1;
+	display: grid;
+	align-content: start;
+	align-items: center;
+	grid-template-columns: max-content 1fr;
 }
 
-#tabpanel-metadata hbox, #hbox-testFrame {
+#metadata-grid > label:nth-child(2n + 1) {
+	justify-self: right;
+}
+
+.button-row {
+	display: grid;
+	grid-template-columns: 1fr max-content;
+}
+
+#tabpanel-metadata input {
+	height: 1.5em;
+}
+
+#hbox-testFrame {
 	-moz-box-align: center;
 }
 
@@ -65,7 +79,7 @@
 	height:200px;
 }
 
-listbox {
+richlistbox {
 	min-width:200px;
 }
 
@@ -95,12 +109,50 @@ vbox > splitter {
 	cursor: row-resize;
 }
 
-listbox[disabled], toolbarbutton[disabled] {
+/* Adapted from Mozilla common-shared.css */
+/* https://searchfox.org/mozilla-central/rev/2f5ed7b7244172d46f538051250b14fb4d8f1a5f/toolkit/themes/shared/in-content/common-shared.css */
+
+select[size][multiple],
+listheader,
+richlistbox {
+  appearance: none;
+  margin-inline: 0;
+  background-color: #fff;
+  border: 1px solid #ccc;
+}
+
+listheader {
+  padding-bottom: 1px;
+}
+
+treecol {
+	appearance: none;
+	border: none;
+}
+
+listheader + richlistbox {
+  margin-top: 0;
+  border-top: none;
+}
+
+select[size][multiple] > option,
+treechildren::-moz-tree-row {
+  padding: 0.3em;
+  margin: 0;
+  border: none;
+  background-image: none;
+}
+
+richlistitem[selected] menulist:focus-visible {
+  outline-offset: -2px;
+}
+
+richlistbox[disabled], toolbarbutton[disabled] {
 	opacity: 0.6;
 	pointer-events: none;
 }
 
-dialog listbox > listitem[disabled] {
+dialog richlistbox > richlistitem[disabled] {
 	font-weight: 600;
 }
 
@@ -110,12 +162,14 @@ dialog listbox > listitem[disabled] {
 
 #checkboxes-translatorType checkbox {
 	margin-right: 10px;
+	display: inline-block;
 }
 
 #tabpanel-metadata label:first-child {
 	text-align: right;
 }
 
-.listcol-testMessage {
-	width: 200px;
+#right-pane textarea {
+	margin-right: 5px;
+	margin-bottom: 5px;
 }
diff --git a/chrome/skin/default/zotero/zotero.css b/chrome/skin/default/zotero/zotero.css
index 0833746944..08c6de3883 100644
--- a/chrome/skin/default/zotero/zotero.css
+++ b/chrome/skin/default/zotero/zotero.css
@@ -111,7 +111,11 @@ zoterofilesyncstatus {
 
 richlistitem {
 	padding: 0.2em 0.4em;
+}
+
+richlistitem, richlistitem > * {
 	overflow-x: hidden;
+	white-space: nowrap;
 	text-overflow: ellipsis;
 }