Steps to reproduce:
- Go to Site's Content > Forms and click to add a new form;
- Click to add a new "Form Text" type of field;
- Click on the placeholder "Enter body text".
The add button that appears on the left side of the editor should have a plus sign icon and when it's clicked on, the following error shows on the browser's console:
The button should have the respective icon and no error should be thrown on the browser's console making it possible to complete the task.