Seems to affect master only.

To reproduce.

1. Create a quiz with at least one question
2. As a student attempt the quiz
3. As a teacher view the attempts
4. Try to delete the attempt. Nothing happens after pressing Yes in the confirmation dialogue.
5. Checking the JS console, the following can be seen

   Uncaught TypeError: a.closest is not a function

   at g (changechecker.js:100)

   at Object.m [as markFormAsDirty] (changechecker.js:203)

   at javascript-static.js:297

   at Y.Subscriber._notify (yui_combo.php?rollup/3.17.2/yui-moodlesimple.js:13680)

   at Y.Subscriber.notify (yui_combo.php?rollup/3.17.2/yui-moodlesimple.js:13709)

   at Y.CustomEvent._notify (yui_combo.php?rollup/3.17.2/yui-moodlesimple.js:13372)

   at Y.CustomEvent._procSubs (yui_combo.php?rollup/3.17.2/yui-moodlesimple.js:13498)

   at Y.CustomEvent.CEProto.fireComplex (yui_combo.php?rollup/3.17.2/yui-moodlesimple.js:27713)

   at Y.CustomEvent._fire (yui_combo.php?rollup/3.17.2/yui-moodlesimple.js:13445)

   at CONFIRM.fire (yui_combo.php?rollup/3.17.2/yui-moodlesimple.js:14600)