Ensure all settings for the MathJax filter are set to the admin defaults. Set the MathJax URL to use version 2.7.3 or the current default version 2.7.9 https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.9/MathJax.js Ensure the MathJax filter is enabled (should be by default). Go to a course. Create a new page within the course. Under page content, add some math equations using the equation editor. Here's an example: $$ x\ =\ \frac{\sqrt{144}}{2}\ \times\ (y\ +\ 12) $$  Save the page and view it. Check that the filter works and that the equation is shown. Right click on the displayed equation Select "Accessibility" > "Explorer" Ensure that options such as "Collapsible Math", "Highlight" and "Background" are enabled. Reload the page to ensure these settings persist and the equation still displays correctly. Make sure that there are no JavaScript errors.