Steps to reproduce:
- Open a page containing a maths formula.
- Select the formula and click 'Edit' in the context menu. Change the formula (alternatively, switch to inline or block display).
- Decide that you made a mistake. Click 'Cancel'.
Result:
Your changes are preserved anyway. Pressing 'Cancel' appears to be functionally identical to pressing 'Done'.
Expected outcome:
Your changes would actually be cancelled. (What exactly is the Cancel button supposed to do, if not cancel your changes?)