Actual behavior:

If an element in the course index is collapsed and quickly navigated to the next element using the arrow key navigation during the collapse animation (arrow key down), the focus is "collapsed" and can only be restored within the course index by reloading the page.

Expected behavior:

As soon as an element in the course index is collapsed using keyboard navigation, the sub-elements should no longer be accessible. The focus should not be able to be caught in collapsed elements.

Description:

• Navigate to the course index using the tab key
• Navigate to a collapsible element using the arrow keys
• Expand element (space bar) if currently collapsed

• Collapse the element (space bar) and then navigate directly to the next element using the down arrow key:

• The keyboard focus "disappears" in the substructure of the collapsed element and cannot be restored within the course index using standard methods (ESC key, space bar, etc.).
• Within the course index it is only possible to scroll using the keyboard, no elements can be focused.