When the topics are collapsed, tabbing through the interface completely skips over the ability to show one topic within the full page of other collapsed topics. The tabbing takes you to the 'show one topic only' view, which removes the rest of the content on the screen and changes the way you navigate to other topics (instead you have to use the navigation menu or the back or next links at the bottom of the page). This might confuse users.

Although this is an improvement from not being able to tab to anything (like in Moodle 3.1), ideally disabled users should get the same navigation options as those without disabilities. E.g. The tabbing should allow them to choose to view the topic in line (surrounded by the other collapsed topic titles), or to view just that topic (which is currently their only option if using the keyboard to navigate).

Also, they should also be able to use the show all / collapse all links by being able to tab to these. Currently tabbing through the interface skips over these, so they again have less navigation options than those using a mouse to navigate.