I defined a hot key on Alt-C to use class view (Sidebar.Class View), the way one can do with Atl-X for project view.
The class view opens, but the keyboard is not directed to it, so it is not possible to use with cursor keys. After having clicked on it with mouse it starts to work, but only as long as you stay there. After changing back to editor, class view looses focus again till next click.
Au contraire, Alt-X opens Project View, focus falls there, and it can be browsed with cursor keys.