Sometimes Properties won't open, bug?

Pianoleo, thanks for clarification! I had totally missed the Way ctrl/cmd-0 works, but now it makes sense.

As I understand it, Ctrl/Cmd+0 should be used to restore whatever panels were previously open, so in my eyes it’s not a bug that Cmd/Ctrl+8 doesn’t work, it’s a bug that Cmd/Ctrl+7, 8 and 9 sometimes work.

Derek, I totally agree, I can’t really see the point in “restoring” the panels?

I would certainly prefer to be able to hide all panels with CTRL/CMD+0 and the call them back individually when needed using the other shortcuts.

In most cases I have all panels closed and just opens them occasionally when I can’t remember the shortcut or when editing something in the Properties. I don’t have any “default state” I’d like to return to.
This might possibly be a smart feature even though I, obviously, hadn’t understood it yet. But it would be even better if it could work both ways. I.e. both possibility to restore the panels and/or open up any single panel after closing them with ctrl/cmd-0.