That did solve the problem… in fact only reinstallation of lubuntu-desktop solved the problem. However, now I find few KDE applications and packages installed (which I hadn’t installed on purpose – pretty sure). It wasn’t the case earlier. Any idea as to why it is so ? Some of the applications are:
KSysGuard
KDE PartitionManager
KDE System Settings
In fact, now on the desktop graphical login screen, I get an on-screen keyboard (like on Android devices) on my primary monitor, and the usual login screen on the secondary monitor, on a dual-monitor setup. What gives ?
That said, we know you reinstalled xorg. It has a virtual dependency on x-terminal-emulator. I’ve seen weird situations before where if no terminal is installed, the selection of terminal would be kind of random from that list. Perhaps konsole pulls in some other KDE stuff. I wouldn’t expect it to, but maybe. KDE has been pretty good about making standalone applications with as little dependencies as possible lately. If only they would fix Plasma, but I digress…
It’s also a remote possibility that when you used apt, you used the option to install suggested packages (perhaps you had previously set this as the default via APT::Install-Suggests "true" somewhere in /etc/apt/apt.conf.d/). I say this because qtvirtualkeyboard-plugin is a suggested package of sddm.
I bet if you purge the virtual keyboard it’ll fix the latter problem. And if you have any Plasma packages get rid of those. Should be good then.