STEPS TO REPRODUCE:
- Login with Admin or with an user
- Go to a page, select some text (or a word)
- Press CTRL + M and fill in some annotation text
- Click "Add annotation" button
The annotation is added.
After clicking "Add annotation" button, the annotation text box remains displayed (screenshot attached) and shows an endlessly spinning wheel until refresh of the page is performed. Tested on IE, Edge, Firefox and Chrome.