Comment by lproven

None of that is correct.

No, it's not in all OSes. I wish it were.

No, it's not in all native apps. KDE reinvents its own set of keystrokes, for instance, and half the KDE apps have no menu bars any more... And there's no global way to force them either.

Yes, the control panel and RegEdit are totally keyboard controllable.

You can literally just unplug the mouse from a Windows desktop and it remains totally 100% operable.

Some apps may not, because the developers didn't do their jobs right, but the OS is.

How else could blind people use PCs?