diff --git a/chrome/content/zotero/createParentDialog.xul b/chrome/content/zotero/createParentDialog.xul
index e92707d6cf..e40f83280d 100644
--- a/chrome/content/zotero/createParentDialog.xul
+++ b/chrome/content/zotero/createParentDialog.xul
@@ -5,7 +5,9 @@
 <?xml-stylesheet href="chrome://zotero-platform/content/overlay.css" type="text/css"?>
 <?xml-stylesheet href="chrome://zotero-platform/content/zotero-react-client.css"?>
 
-<!DOCTYPE window SYSTEM "chrome://zotero/locale/zotero.dtd">
+<!DOCTYPE dialog [
+		<!ENTITY % zoteroDTD SYSTEM "chrome://zotero/locale/zotero.dtd"> %zoteroDTD;
+]>
 
 <dialog
 	id="zotero-parent-dialog"
@@ -23,7 +25,10 @@
 	xmlns:html="http://www.w3.org/1999/xhtml"
 	style="padding:20px 15px;width:400px;">
 
+	<script src="chrome://global/content/globalOverlay.js"/>
+	<script src="chrome://global/content/editMenuOverlay.js"/>
 	<script src="include.js"/>
+	<script src="editContextMenu.js"/>
 	<script src="lookup.js"/>
 	<script src="createParentDialog.js"/>
 	<script src="components/createParent/createParent.js"/>
diff --git a/chrome/content/zotero/editContextMenu.js b/chrome/content/zotero/editContextMenu.js
new file mode 100644
index 0000000000..f586bc346e
--- /dev/null
+++ b/chrome/content/zotero/editContextMenu.js
@@ -0,0 +1,133 @@
+/*
+    ***** BEGIN LICENSE BLOCK *****
+
+    Copyright © 2021 Corporation for Digital Scholarship
+                     Vienna, Virginia, USA
+                     https://www.zotero.org
+
+    This file is part of Zotero.
+
+    Zotero is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Zotero is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with Zotero.  If not, see <http://www.gnu.org/licenses/>.
+
+    ***** END LICENSE BLOCK *****
+*/
+
+// Support context menus on HTML text boxes
+//
+// Adapted from editMenuOverlay.js in Fx68
+// This entire file can be replaced with that file when Zotero upgrades.
+//
+// Currently it requires both:
+// `chrome://global/content/editMenuOverlay.js`
+// `chrome://global/content/globalOverlay.js`
+
+window.addEventListener(
+	"DOMContentLoaded",
+	() => {
+		let commands = document.createElement('commandset');
+
+		let commandSetAll = document.createElement('commandset');
+		commandSetAll.id = 'editMenuCommandSetAll';
+		commandSetAll.setAttribute('commandupdater', 'true');
+		commandSetAll.setAttribute('events', 'focus,select');
+		commandSetAll.setAttribute('oncommandupdate', 'goUpdateGlobalEditMenuItems()');
+		commands.appendChild(commandSetAll);
+
+		let commandSetUndo = document.createElement('commandset');
+		commandSetUndo.id = 'editMenuCommandSetUndo';
+		commandSetUndo.setAttribute('commandupdater', 'true');
+		commandSetUndo.setAttribute('events', 'undo');
+		commandSetUndo.setAttribute('oncommandupdate', 'goUpdateUndoEditMenuItems()');
+		commands.appendChild(commandSetUndo);
+
+		let commandSetPaste = document.createElement('commandset');
+		commandSetPaste.id = 'editMenuCommandSetPaste';
+		commandSetPaste.setAttribute('commandupdater', 'true');
+		commandSetPaste.setAttribute('events', 'clipboard');
+		commandSetPaste.setAttribute('oncommandupdate', 'goUpdatePasteMenuItems()');
+		commands.appendChild(commandSetPaste);
+
+		const createCommand = function (name) {
+			let command = document.createElement('command');
+			command.id = `cmd_${name}`;
+			command.setAttribute('oncommand', `goDoCommand('cmd_${name}')`);
+			return command;
+		};
+
+		commands.appendChild(createCommand('undo'));
+		commands.appendChild(createCommand('cut'));
+		commands.appendChild(createCommand('copy'));
+		commands.appendChild(createCommand('paste'));
+		commands.appendChild(createCommand('delete'));
+		commands.appendChild(createCommand('selectAll'));
+
+		let container = document.querySelector("commandset") || document.documentElement;
+		container.appendChild(commands);
+	},
+	{ once: true }
+);
+
+function createContentAreaContextMenuItem(name) {
+	let item = document.createElement('menuitem');
+	item.id = 'context-' + name.toLowerCase();
+	item.setAttribute('label', Zotero.Intl.strings[name + 'Cmd.label']);
+	item.setAttribute('accesskey', Zotero.Intl.strings[name + 'Cmd.accesskey']);
+	item.setAttribute('command', 'cmd_' + name);
+	return item;
+}
+
+function createContentAreaContextMenu() {
+	let menupopup = document.createElement('menupopup');
+	menupopup.id = 'contentAreaContextMenu';
+
+	menupopup.appendChild(createContentAreaContextMenuItem('undo'));
+	let undoSep = document.createElement('menuseparator');
+	undoSep.id = 'context-sep-undo';
+	menupopup.appendChild(undoSep);
+	menupopup.appendChild(createContentAreaContextMenuItem('cut'));
+	menupopup.appendChild(createContentAreaContextMenuItem('copy'));
+	menupopup.appendChild(createContentAreaContextMenuItem('paste'));
+	menupopup.appendChild(createContentAreaContextMenuItem('delete'));
+	let pasteSep = document.createElement('menuseparator');
+	pasteSep.id = 'context-sep-paste';
+	menupopup.appendChild(pasteSep);
+	menupopup.appendChild(createContentAreaContextMenuItem('selectAll'));
+
+	document.documentElement.appendChild(menupopup);
+	return menupopup;
+}
+
+window.addEventListener("contextmenu", e => {
+	const HTML_NS = "http://www.w3.org/1999/xhtml";
+	let needsContextMenu =
+		e.target.ownerDocument == document &&
+		!e.defaultPrevented &&
+		e.target.parentNode.nodeName != "moz-input-box" &&
+		((["textarea", "input"].includes(e.target.localName) &&
+			e.target.namespaceURI == HTML_NS) ||
+			e.target.closest("search-textbox"));
+
+	if (!needsContextMenu) {
+		return;
+	}
+
+	let popup = document.getElementById("contentAreaContextMenu")
+		|| createContentAreaContextMenu();
+
+	goUpdateGlobalEditMenuItems(true);
+	popup.openPopupAtScreen(e.screenX, e.screenY, true);
+	// Don't show any other context menu at the same time. There can be a
+	// context menu from an ancestor too but we only want to show this one.
+	e.preventDefault();
+});
diff --git a/chrome/content/zotero/xpcom/intl.js b/chrome/content/zotero/xpcom/intl.js
index 537618f1fa..f4cf974d63 100644
--- a/chrome/content/zotero/xpcom/intl.js
+++ b/chrome/content/zotero/xpcom/intl.js
@@ -76,7 +76,7 @@ Zotero.Intl = new function () {
 		Zotero.rtl = (Zotero.dir === 'rtl');
 		
 		this.strings = {};
-		const intlFiles = ['zotero.dtd'];
+		const intlFiles = ['zotero.dtd', 'mozilla/editMenuOverlay.dtd'];
 		for (let intlFile of intlFiles) {
 			let localeXML = Zotero.File.getContentsFromURL(`chrome://zotero/locale/${intlFile}`);
 			let regexp = /<!ENTITY ([^\s]+)\s+"([^"]+)/g;