diff --git a/nbgrader/docs/source/conf.py b/nbgrader/docs/source/conf.py
index 30e61a1f6..b5356823a 100644
--- a/nbgrader/docs/source/conf.py
+++ b/nbgrader/docs/source/conf.py
@@ -287,6 +287,10 @@
 # If true, do not generate a @detailmenu in the "Top" node's menu.
 #texinfo_no_detailmenu = False
 
+linkcheck_ignore = [
+    # Assume GitHub contributor search links for this repo are always valid
+    r"https://github.com/search\?q=repo%3Ajupyter%2Fnbgrader\+involves%3A.*type=Issues",
+]
 
 # Example configuration for intersphinx: refer to the Python standard library.
 intersphinx_mapping = {'http://docs.python.org/': None}
diff --git a/nbgrader/server_extensions/formgrader/base.py b/nbgrader/server_extensions/formgrader/base.py
index d5bf2ec4d..1593b0ef2 100644
--- a/nbgrader/server_extensions/formgrader/base.py
+++ b/nbgrader/server_extensions/formgrader/base.py
@@ -4,6 +4,7 @@
 
 from tornado import web
 from jupyter_server.base.handlers import JupyterHandler
+from jupyter_server.utils import url_path_join, url_is_absolute
 from ...api import Gradebook
 from ...apps.api import NbGraderAPI
 
@@ -41,7 +42,10 @@ def gradebook(self):
 
     @property
     def mathjax_url(self):
-        return self.settings['mathjax_url']
+        url = self.settings.get("mathjax_url", "")
+        if not url or url_is_absolute(url):
+            return url
+        return url_path_join(self.base_url or "/", url)
 
     @property
     def exporter(self):
diff --git a/nbgrader/server_extensions/formgrader/formgrader.py b/nbgrader/server_extensions/formgrader/formgrader.py
index d5806dfb6..f49a777c6 100644
--- a/nbgrader/server_extensions/formgrader/formgrader.py
+++ b/nbgrader/server_extensions/formgrader/formgrader.py
@@ -107,9 +107,6 @@ def load_jupyter_server_extension(nbapp):
     nbapp.log.info("Loading the formgrader nbgrader serverextension")
     webapp = nbapp.web_app
 
-    # Save which kind of application is running : Jupyterlab like or classic Notebook
-    webapp.settings['is_jlab'] = not (nbapp.name == 'jupyter-notebook')
-
     formgrader = FormgradeExtension(parent=nbapp)
 
     # compatibility between notebook.notebookapp.NotebookApp and jupyter_server.serverapp.ServerApp
diff --git a/nbgrader/server_extensions/formgrader/handlers.py b/nbgrader/server_extensions/formgrader/handlers.py
index 0fa8a9404..7fff1b3d5 100644
--- a/nbgrader/server_extensions/formgrader/handlers.py
+++ b/nbgrader/server_extensions/formgrader/handlers.py
@@ -17,7 +17,6 @@ def get(self):
             "manage_assignments.tpl",
             url_prefix=self.url_prefix,
             base_url=self.base_url,
-            is_lab=int(self.settings['is_jlab']),
             windows=(sys.prefix == 'win32'),
             course_id=self.api.course_id,
             exchange=self.api.exchange_root,
@@ -108,10 +107,9 @@ def get(self, submission_id):
             'index': ix,
             'total': len(indices),
             'base_url': self.base_url,
-            'my_mathjax_url': self.mathjax_url if self.settings['is_jlab'] else self.base_url + '/' + self.mathjax_url,
+            'my_mathjax_url': self.mathjax_url,
             'student': student_id,
             'last_name': submission.student.last_name,
-            'last_name': submission.student.last_name,
             'first_name': submission.student.first_name,
             'notebook_path': self.url_prefix + '/' + relative_path
         }
diff --git a/nbgrader/server_extensions/formgrader/static/js/jupyterlab_utils.js b/nbgrader/server_extensions/formgrader/static/js/jupyterlab_utils.js
deleted file mode 100644
index 7e9bb9783..000000000
--- a/nbgrader/server_extensions/formgrader/static/js/jupyterlab_utils.js
+++ /dev/null
@@ -1,10 +0,0 @@
-/*
- * Module of data to send to Jupyterlab's nbgrader extension to perform actions.
- */
-
-var jlab_go_to_path = function(directory_path){
-    return JSON.stringify({
-               "command": "filebrowser:go-to-path",
-               "arguments": {"path": directory_path}
-           });
-}
\ No newline at end of file
diff --git a/nbgrader/server_extensions/formgrader/static/js/manage_assignments.js b/nbgrader/server_extensions/formgrader/static/js/manage_assignments.js
index 531c64eb8..41e8ed0ed 100644
--- a/nbgrader/server_extensions/formgrader/static/js/manage_assignments.js
+++ b/nbgrader/server_extensions/formgrader/static/js/manage_assignments.js
@@ -34,7 +34,6 @@ var AssignmentUI = Backbone.View.extend({
         this.listenTo(this.model, "request", this.animateSaving);
         this.listenTo(this.model, "sync", this.closeModal);
 
-        this.is_lab = options.is_lab || false;
         this.render();
     },
 
@@ -97,22 +96,14 @@ var AssignmentUI = Backbone.View.extend({
 
     render: function () {
         this.clear();
-        var this_assignment = this;
+
         // assignment name
         var name = this.model.get("name")
         this.$name.attr("data-order", name);
 
-        /* Append link with :
-         *     - href if this is a Notebook<7 environment
-         *     - click listener to send message to iframe parent if this is Jupyter Lab environment
-         */
         this.$name.append($("<a/>")
             .text(name)
-            .attr("target", self.is_lab ? undefined : "_blank")
-            .attr("href", self.is_lab ? undefined : base_url + "/tree/" + url_prefix + "/" + this.model.get("source_path"))
-            .click(self.is_lab ? function(){
-                window.parent.postMessage(jlab_go_to_path(url_prefix + "/" + this_assignment.model.get("source_path")), '*');
-            } : undefined)
+            .map(linkTo("directory", url_prefix + "/" + this.model.get("source_path")))
         );
 
         // duedate
@@ -154,16 +145,8 @@ var AssignmentUI = Backbone.View.extend({
         // preview student version
         var release_path = this.model.get("release_path");
         if (release_path) {
-            /* Append link with :
-             *     - href if this is a Notebook<7 environment
-             *     - click listener to send message to iframe parent if this is Jupyter Lab environment
-             */
             this.$preview.append($("<a/>")
-                .attr("target", self.is_lab ? undefined : "_blank")
-                .attr("href", self.is_lab ? undefined : base_url + "/tree/" + url_prefix + "/" + release_path)
-                .click(self.is_lab ? function(){
-                        window.parent.postMessage(jlab_go_to_path(url_prefix + "/" + release_path), '*');
-                    } : undefined)
+                .map(linkTo("directory", url_prefix + "/" + release_path))
                 .append($("<span/>")
                     .addClass("glyphicon glyphicon-search")
                     .attr("aria-hidden", "true")));
@@ -215,20 +198,20 @@ var AssignmentUI = Backbone.View.extend({
         // generate feedback
         if (num_submissions > 0) {
             this.$generate_feedback.append($("<a/>")
-		.attr("href", "#")
+                .attr("href", "#")
                 .click(_.bind(this.generate_feedback, this))
-		.append($("<span/>")
-		   .addClass("glyphicon glyphicon-comment")
+                .append($("<span/>")
+                    .addClass("glyphicon glyphicon-comment")
                    .attr("aria-hidden", "true")));
         }
 
         //  feedback
         if (num_submissions > 0) {
             this.$release_feedback.append($("<a/>")
-		.attr("href", "#")
+                .attr("href", "#")
                 .click(_.bind(this.release_feedback, this))
-		.append($("<span/>")
-		   .addClass("glyphicon glyphicon-envelope")
+                .append($("<span/>")
+                    .addClass("glyphicon glyphicon-envelope")
                    .attr("aria-hidden", "true")));
         }
 
@@ -579,7 +562,7 @@ var createAssignmentModal = function () {
     modal = createModal("add-assignment-modal", "Add New Assignment", body, footer);
 };
 
-var loadAssignments = function (is_lab=false) {
+var loadAssignments = function () {
     var tbl = $("#main-table");
 
     models = new Assignments();
@@ -592,7 +575,6 @@ var loadAssignments = function (is_lab=false) {
                 var view = new AssignmentUI({
                     "model": model,
                     "el": insertRow(tbl),
-                    "is_lab": is_lab
                 });
                 views.push(view);
             });
@@ -605,8 +587,6 @@ var loadAssignments = function (is_lab=false) {
 var models = undefined;
 var views = [];
 
-var is_lab = is_lab || false;
-
 $(window).on('load', function () {
-    loadAssignments(is_lab);
+    loadAssignments();
 });
diff --git a/nbgrader/server_extensions/formgrader/static/js/utils.js b/nbgrader/server_extensions/formgrader/static/js/utils.js
index e5adf5fa8..05c50aec1 100644
--- a/nbgrader/server_extensions/formgrader/static/js/utils.js
+++ b/nbgrader/server_extensions/formgrader/static/js/utils.js
@@ -87,3 +87,44 @@ var insertDataTable = function (tbl) {
         }]
     });
 };
+
+var linkTo = function (type, path) {
+    /*
+     * Connect a link in the appropriate manner for the context.
+     * - If we're in the outermost frame, assume notebook and use an href.
+     * - If we're in an iframe, assume lab and send a message.
+     */
+    if (window === window.top) {
+        var prefix = {
+            notebook: "/notebooks/",
+            file: "/edit/",
+            directory: "/tree/"
+        }[type];
+
+        return (_, el) => {
+            return $(el)
+                .attr("href", prefix + path)
+                .attr("target", "_blank")[0];
+        };
+    } else {
+        var command = {
+            notebook: "docmanager:open",
+            file: "docmanager:open",
+            directory: "filebrowser:go-to-path",
+        }[type];
+
+        return (_, el) => {
+            return $(el)
+                .attr("href", "#")
+                .click(() => {
+                    window.parent.postMessage(
+                        JSON.stringify({
+                            "command": command,
+                            "arguments": {"path": path}
+                        }),
+                        "*"
+                    );
+                })[0];
+        }
+    }
+}
diff --git a/nbgrader/server_extensions/formgrader/templates/base.tpl b/nbgrader/server_extensions/formgrader/templates/base.tpl
index 56eb423fb..b2c6168f9 100644
--- a/nbgrader/server_extensions/formgrader/templates/base.tpl
+++ b/nbgrader/server_extensions/formgrader/templates/base.tpl
@@ -10,7 +10,6 @@
   <script src="{{ base_url }}/formgrader/static/components/datatables.net-bs/js/dataTables.bootstrap.min.js"></script>
   <script src="{{ base_url }}/formgrader/static/js/backbone_xsrf.js"></script>
   <script src="{{ base_url }}/formgrader/static/js/utils.js"></script>
-  <script src="{{ base_url }}/formgrader/static/js/jupyterlab_utils.js"></script>
 
   <link rel="stylesheet" href="{{ base_url }}/formgrader/static/components/bootstrap/css/bootstrap.min.css" />
   <link rel="stylesheet" href="{{ base_url }}/formgrader/static/components/datatables.net-bs/css/dataTables.bootstrap.min.css">
diff --git a/nbgrader/server_extensions/formgrader/templates/formgrade/formgrade_macros.html.j2 b/nbgrader/server_extensions/formgrader/templates/formgrade/formgrade_macros.html.j2
index e014b1f2e..b5a3133f9 100644
--- a/nbgrader/server_extensions/formgrader/templates/formgrade/formgrade_macros.html.j2
+++ b/nbgrader/server_extensions/formgrader/templates/formgrade/formgrade_macros.html.j2
@@ -20,6 +20,7 @@ var base_url = "{{ resources.base_url }}/formgrader";
 <script src="{{ resources.base_url }}/formgrader/static/js/formgrade_keyboardmanager.js"></script>
 <script src="{{ resources.base_url }}/formgrader/static/js/formgrade_models.js"></script>
 <script src="{{ resources.base_url }}/formgrader/static/js/formgrade.js"></script>
+<script src="{{ resources.base_url }}/formgrader/static/js/utils.js"></script>
 <script type="text/javascript">
 function toggle_name(on) {
   $(".name-shown").tooltip('hide');
@@ -33,12 +34,11 @@ function toggle_name(on) {
   }
 }
 
-function jlab_open_notebook(notebook_path) {
-  return JSON.stringify({
-    "command": "docmanager:open",
-    "arguments": {"path": notebook_path}
+$(document).ready(function() {
+  $("[data-link]").each(function() {
+    $(this).map(linkTo("notebook", $(this).data("link"))).removeAttr("data-link");
   });
-}
+});
 </script>
 
 <link rel="stylesheet" href="{{ resources.base_url }}/formgrader/static/components/bootstrap/css/bootstrap.min.css" />
@@ -64,20 +64,12 @@ function jlab_open_notebook(notebook_path) {
             <li><a href="{{ resources.base_url }}/formgrader/gradebook/{{ resources.assignment_id }}/{{ resources.notebook_id }}">{{ resources.notebook_id }}</a></li>
             <li class="active live-notebook">
               <a class="name-hidden" data-toggle="tooltip" data-placement="bottom" title="Open live notebook"
-                {%- if is_lab -%}
-                onclick='window.parent.postMessage(jlab_open_notebook("{{ resources.notebook_path }}"), "*");'
-                {%- else -%}
-                target="_blank" href="{{ resources.base_url }}/notebooks/{{ resources.notebook_path }}"
-                {%- endif -%}
+                data-link="{{ resources.notebook_path }}"
               >
                 Submission #{{ resources.index + 1 }}
               </a>
               <a class="name-shown" data-toggle="tooltip" data-placement="bottom" title="Open live notebook"
-                {%- if is_lab -%}
-                onclick='window.parent.postMessage(jlab_open_notebook("{{ resources.notebook_path }}"), "*"); '
-                {%- else -%}
-                target="_blank" href="{{ resources.base_url }}/notebooks/{{ resources.notebook_path }}"
-                {%- endif -%}
+                data-link="{{ resources.notebook_path }}"
               >
                 {%- if resources.last_name and resources.first_name -%}
                 {{ resources.last_name }}, {{ resources.first_name }}
@@ -107,4 +99,4 @@ function jlab_open_notebook(notebook_path) {
   $('span.glyphicon.name-hidden').tooltip({title: "Show student name", placement: "bottom", trigger: "hover"});
   $('span.glyphicon.name-shown').tooltip({title: "Hide student name", placement: "bottom", trigger: "hover"});
   </script>
-{% endmacro %}
\ No newline at end of file
+{% endmacro %}
diff --git a/nbgrader/server_extensions/formgrader/templates/manage_assignments.tpl b/nbgrader/server_extensions/formgrader/templates/manage_assignments.tpl
index 1fb2ab3cf..51b6969f8 100644
--- a/nbgrader/server_extensions/formgrader/templates/manage_assignments.tpl
+++ b/nbgrader/server_extensions/formgrader/templates/manage_assignments.tpl
@@ -3,7 +3,6 @@
 {%- block head -%}
 <script>
 var url_prefix = "{{ url_prefix }}";
-var is_lab = {% if is_lab %}true{% else %}false{% endif %};
 </script>
 
 <script src="{{ base_url }}/formgrader/static/js/manage_assignments.js"></script>
diff --git a/yarn.lock b/yarn.lock
index 95809c055..9880f33f8 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2133,9 +2133,9 @@ caniuse-lite@^1.0.30001349:
   integrity sha512-Sd6pjJHF27LzCB7pT7qs+kuX2ndurzCzkpJl6Qct7LPSZ9jn0bkOA8mdgMgmqnQAWLVOOGjLpc+66V57eLtb1g==
 
 canvas@^2.6.1:
-  version "2.11.0"
-  resolved "https://registry.yarnpkg.com/canvas/-/canvas-2.11.0.tgz#7f0c3e9ae94cf469269b5d3a7963a7f3a9936434"
-  integrity sha512-bdTjFexjKJEwtIo0oRx8eD4G2yWoUOXP9lj279jmQ2zMnTQhT8C3512OKz3s+ZOaQlLbE7TuVvRDYDB3Llyy5g==
+  version "2.11.2"
+  resolved "https://registry.yarnpkg.com/canvas/-/canvas-2.11.2.tgz#553d87b1e0228c7ac0fc72887c3adbac4abbd860"
+  integrity sha512-ItanGBMrmRV7Py2Z+Xhs7cT+FNt5K0vPL4p9EZ/UX/Mu7hFbkxSjKF2KVtPwX7UYWp7dRKnrTvReflgrItJbdw==
   dependencies:
     "@mapbox/node-pre-gyp" "^1.0.0"
     nan "^2.17.0"