How to add 3rd party editor to Wagtail 2.2+? - wagtail

Question

We have been using Froala editor within Wagtail for years, and even though Draftail is nice, the end user wants to continue to use Frola, especially as a license fee has been paid for it, and it offers extra functionality that they use.
I have used the following which works great for any version of Wagtail prior to version 2.2:
https://github.com/jaydensmith/wagtailfroala/pull/5/commits/d64d00831375489cfacefa7af697a9e76fb7f175
However in Wagtail version 2.2 this has changed:
https://docs.wagtail.org/en/stable/releases/2.2.html#javascript-templates-in-modal-workflows-are-deprecated, this causes selecting images within Froala to no longer work correctly. You get to pick the image, but it fails to move onto the 2nd dialog to select alignment and then click insert.
It looks like wagtailfroala/static/froala/js/froala.js needs to be changed to add onload to the ModalWorkflow.
$.FE.RegisterCommand('insertImage', {
title: 'Insert Image',
undo: false,
focus: true,
refreshAfterCallback: false,
popup: true,
callback: function () {
var editor = this;
return ModalWorkflow({
url: window.chooserUrls.imageChooser + '?select_format=true',
responses: {
imageChosen: function(imageData) {
editor.edit.off();
var $img = $(imageData.html);
$img.on('load', function() {
_loadedCallback(editor, $(this));
});
// Make sure we have focus.
// Call the event.
editor.edit.on();
editor.events.focus(true);
editor.selection.restore();
editor.undo.saveStep();
// Insert marker and then replace it with the image.
if (editor.opts.imageSplitHTML) {
editor.markers.split();
} else {
editor.markers.insert();
}
var $marker = editor.$el.find('.fr-marker');
$marker.replaceWith($img);
editor.html.wrap();
editor.selection.clear();
editor.events.trigger('contentChanged');
editor.undo.saveStep();
editor.events.trigger('image.inserted', [$img]);
}
}
});
},
plugin: 'image'
});
But what needs to be added to make it work? I can't find any documentation or examples on how do to this? Please help or point me in the direction of the documentation for how this should be done.
Thank you so much in advance.