Please note that this bug relates only to Right-to-left UI environments.

Repro stpes

1. Login to Moodle.
2. Install the Hebrew language pack.
3. Verify in the site settings that the Atto editor is active and the first in order (SERVER_URL/admin/settings.php?section=manageeditors).
4. Change the UI language of Moodle to English.
5. Add (for example) a "Label" activity. 
6. In the Atto editor, write some text and then click the "HTML" button.
7. Verify that the HTML mode/view is working correctly.
8. Change the UI language of Moodle to Hebrew.
9. Click the "HTML" button again.

Actual results

No HTML code is displayed on the screen.

Expected results

HTML code should be displayed on the screen.