Project: moodle
Issue MDL-44844: Custom menu broken in all non-bootstrap themes. 
The custom menu code uses the "YUI3 menunav" module (which is deprecated). For some reason this is broken in master (probably because of a yui update). Bootstrapbase provides it's own renderer for this which uses the yui module for bootstrap so it's not affected. I noticed this was broken in mod_assign and fixed it by converting to an action-menu - this doesn't really help with custom menu though.
Story points: 13