Hi all,

We recently found out that as long as there is a Atto editor in the form on a pop up dialog. The focus on a browser failed to enter the dialog.

The steps we could reproduce this issue:

1. Login as admin
2. Click Calendar
3. Do not use mouse, instead, hit the Tab button on the keyboard, you could see the focus is moving through the links and buttons on the page.
4. When the focus gets to New event tab, hit "Enter" on the keyboard. 
5. Then if we keep pressing "Tab" button, the focus is supposed to go through the fields in the form that pops up. But currently, it jumps out of the pop-up dialog, it is back to the background page again. Which results in that , on a screen reader, the form is open, but next item after opening the form is not form item. 

If anyone can test this page with a screen reader should see what I mean. Also on a browser, we should be able to see what happen. But this only happens when opening the New event form first time after refreshing. There might be race condition in js here.

As long as we pragmatically remove the Atto editor, this pops up works fine. The focus will stay in the form after opening. But of course this is not a realistic solution.