Just like in Gnome-shell, wherein you can restart the X-screen with a terminal command 'r' without closing any of the running applications, is there something in Xubuntu which could serve the same purpose?
I'm not a Xubuntu user, but I did a little bit of digging. According to this page (scroll down to the bottom), you can create custom keyboard shortcuts in the keyboard preferences dialog.
So, you can create your own shortcut here. Choose an appropriate shortcut, such as Ctrl+Alt+R and map it to
This is basically what Gnome Shell's R command does, and it's completely different from using Ctrl+Alt+Backspace to kill the X server. When you kill the X server, every program you have open dies, too. When you run