Followup to bug 17616.
Browser: Firefox 25.

Steps to reproduce:

1. Go to [Special:RecentChanges] (which has some items collapsed)
2. Focus an arrow to show collapsed changes
3. Press the space bar

What happes:
Nothing.

What I expected:
One of the following alternatives:

1. like a link - like when nothing is focused, the browser scrolls down a page
2. like a button - like when I hit enter, items are either shown or collapsed

In Chrome 28 this bug does not exist (scrolls down a page).

Version: 1.22.0
Severity: minor