[jdally987]

What?.. How could you generalize this across all of "Linux"? Or did you mean something else?

I know what you're talking about, and I'm pretty sure it's a very GNOME-specific problem (or gdm, or whatever login manager they use by default...) because when I started out on Ubuntu earlier this year, there was a very active bug report about it. I could actually probably find it if anyone was curious.

But I've long since ditched gnome because well, I hate it. On KDE now and never had this problem. I'm pretty sure this is not an "all of linux" problem at all though.

[ploek]

I use KDE and I have this problem. Similarly when I switch vterms (I have separate X11-Sessions for my personal and my work-from-home user account), I can briefly see the content of the session that I switched away from (without having locked it) before the lockscreen comes up.

[trilinearnz]

Yes, you're right, I think I've picked up a little confirmation bias based on my choice of distro lineage (in hindsight all have been some derivation of Ubuntu, with some variant of a Gnome 2 / 3 desktop environment). I guess where I was coming from was that I would have expected some mechanism at the lower level of the OS to marshal this kind of behaviour, rather than it being trusted to the window manager. Maybe this stems from security being mainly thought of as a terminal / ssh-level concern, rather than the GUI.

I will give KDE a go!