Thread:Skin talk:Chameleon/Dropdown menu does not work/reply

You use layout clean. From the release notes:

This is a minimalist layout intended for wikis that are not open for general editing. A use case might be a blogging platform. For users, that do not have edit rights, the layout will show only the main content of a wiki page (and the site notice, if set). For users that do have edit rights it will additionally show a sticky full-width navbar above, and a toolbar and an info footer below the main content.