A <div> can't be a direct child of a <ul>. In this case the <ul> tag
didn't make much sense because there isn't a list; just a map.
Note the `z-index` rule which was added in commit 25e1afea48 is ignored
because the map element is statically positioned. I'm not sure why it
was added; can't reproduce the rendering problem both that commit and
commit c5a749212 mention. Maybe back then the element had a `position:
relative` rule or similar somewhere.
57e727ba60