If you use block_myoverview with the function for customfields and the customfield produces so many values for the dropdown that it can't be shown completely on the page, it gets cropped on top and can't be scrolled. So you can't go back to see "All" courses for example.

Steps to reproduce:

1. Add a custom field for courses.
2. Produce about 50 courses with different values for this custom field.
3. Activate the custom fields funktion for block_myoverview.
4. Go to /my/courses.php
5. Open the menu and select one value from the curstom field.
6. Wait for the page to reload, then click again.
7. You won't be able to scroll to the top of the drop down menu.