diff --git a/client/src/components/Draftail/sources/DocumentSource.js b/client/src/components/Draftail/sources/DocumentSource.js
index 9e80cc7d7..86af790ec 100644
--- a/client/src/components/Draftail/sources/DocumentSource.js
+++ b/client/src/components/Draftail/sources/DocumentSource.js
@@ -1,7 +1,6 @@
 import ModalSource from './ModalSource';
 
 const $ = global.jQuery;
-const ModalWorkflow = global.ModalWorkflow;
 
 class DocumentSource extends ModalSource {
   constructor(props) {
@@ -30,7 +29,7 @@ class DocumentSource extends ModalSource {
     }
 
     // eslint-disable-next-line new-cap
-    ModalWorkflow({
+    window.ModalWorkflow({
       url,
       responses: {
         documentChosen: this.parseData,
diff --git a/client/src/components/Draftail/sources/EmbedSource.js b/client/src/components/Draftail/sources/EmbedSource.js
index 4eff09f5a..2360b9f86 100644
--- a/client/src/components/Draftail/sources/EmbedSource.js
+++ b/client/src/components/Draftail/sources/EmbedSource.js
@@ -1,7 +1,6 @@
 import ModalSource from './ModalSource';
 
 const $ = global.jQuery;
-const ModalWorkflow = global.ModalWorkflow;
 
 class EmbedSource extends ModalSource {
   constructor(props) {
@@ -26,7 +25,7 @@ class EmbedSource extends ModalSource {
     $(document.body).on('hidden.bs.modal', this.onClose);
 
     // eslint-disable-next-line new-cap
-    ModalWorkflow({
+    window.ModalWorkflow({
       url: global.chooserUrls.embedsChooser,
       responses: {
         embedChosen: this.parseData,
diff --git a/client/src/components/Draftail/sources/ImageSource.js b/client/src/components/Draftail/sources/ImageSource.js
index 890ae5fa4..9d72f88fd 100644
--- a/client/src/components/Draftail/sources/ImageSource.js
+++ b/client/src/components/Draftail/sources/ImageSource.js
@@ -1,7 +1,6 @@
 import ModalSource from './ModalSource';
 
 const $ = global.jQuery;
-const ModalWorkflow = global.ModalWorkflow;
 
 class ImageSource extends ModalSource {
   constructor(props) {
@@ -20,7 +19,7 @@ class ImageSource extends ModalSource {
     $(document.body).on('hidden.bs.modal', this.onClose);
 
     // eslint-disable-next-line new-cap
-    ModalWorkflow({
+    window.ModalWorkflow({
       url: imageChooser,
       responses: {
         imageChosen: this.parseData,
diff --git a/client/src/components/Draftail/sources/LinkSource.js b/client/src/components/Draftail/sources/LinkSource.js
index 3998c06a1..d46a9154e 100644
--- a/client/src/components/Draftail/sources/LinkSource.js
+++ b/client/src/components/Draftail/sources/LinkSource.js
@@ -1,7 +1,6 @@
 import ModalSource from './ModalSource';
 
 const $ = global.jQuery;
-const ModalWorkflow = global.ModalWorkflow;
 
 // Plaster over Wagtail internals.
 const buildInitialUrl = (entity, openAtParentId, canChooseRoot, pageTypes) => {
@@ -89,7 +88,7 @@ class LinkSource extends ModalSource {
     $(document.body).on('hidden.bs.modal', this.onClose);
 
     // eslint-disable-next-line new-cap
-    ModalWorkflow({
+    window.ModalWorkflow({
       url,
       urlParams,
       responses: {