Add one RTL language package (Hebrew or Arabic or Farsi...) to Moodle (Home ► Site administration ► Language ► Language packs) Switch to Hebrew language (on Moodle's front page) Navigate to any page that display a TinyMCE editor ( ex. the "Description" element inside a user's profile page . OR start a new discussion on a Forum page ) Click the "Add new Image" button, inside the TinyMCE editor. Validate that the Tabs you see in the pop up dialog are all left aligned (as shown in the attached image to this issue) Apply the patch Switch to Design Mode (Home ► Site administration ► Appearance ► Themes ► Theme settings) You might also need to set JavaScript cache to OFF. I added the following lines of code to my config.php file: $CFG->themedesignermode = 1; $CFG->cachejs = false; Clear theme cache (Home ► Site administration ► Appearance ► Themes ► Theme selector) Or even: Purge all caches (Home ► Site administration ► Development ► Purge all caches) "Refresh" (CTRL-R / F5) the page you were viewing and make sure you see the problematic UI element... gone (Solved)