Thanks @ryanjamurphy, not the issue in my case, but helpful in general.
OK. @kepano I thought with minimal 2 none of the main UI elements were hidden by default? But for me it seems the right side ribbon is hidden, is that correct?
If I switch to another theme and open the right sidebar then everything works. But if the sidebar is closed the top right icon becomes unclickable except about a 1px wide sliver.