I recently upgraded to Ubuntu 17.10. As my laptop is rather on the weak side (performance wise), I grew quite uncomfortable with the new desktop as everything seemed to take longer, the laptop being slower overall.
So, I installed LXDE, lubuntu-session packages, etc., to make a transition to the more lightweight LX desktop environment. I am super happy about it, as the system now feels super fast and responsive.
One issue remains: If my session gets locked (by timeout, laptop lid close, or manual lock) I end up with a black and empty screen. Not even a mouse pointer, not responding to any clicks or simple key presses. The only remedy I found was killing/rebooting the entire machine.
After some playing around, I found that Ctrl+Alt+F1 takes me back to the login screen.
I tried to google for this problem, but didn't find any help: Several similar problems were discussed, like having no login screen right after boot (which is not my problem), of another solution talking about "Light Locker Settings" and turning off/on some stuff – but I don't seem to have this menu…
I do not really understand what's going on, and why I seem to end up at the wrong Ctrl-Alt-F* interface.
For me it's only a thing of minor to medium importance, as I found a way to work around it. But, of course, I would be glad if someone could point me to a clean solution.
(A solution is great, but if you could elaborate your answer a bit, I would be very grateful, as I'd really like to learn more about the inner workings of my system.)