For systems that have a large number of courses and categories the number of options in the HTML select can become quite large. May be related to MDL-75539

I have seen a select with over 64K of options listed under

<optgroup label="Course categories">

 <optgroup label="Courses">

For Mac OS X Monterey it can even crash Google Chrome.

Possible suggestion would be

1. to lazy load the items
2. use select2 rather than native select
3. improve the search so not all possible items are listed as options

UX Proposal