How to kill a focused window in Xdotool, but keep some windows out?

I have a shortcut ctrl+alt+x to kill a focused window with

xdotool getwindowfocus windowkill

I am on GNOME, X11 with lightdm, and when all windows have been killed and I press the shortcut gnome-session restarts, is there a way to keep some windows out?

I want to keep out:

• X11
• GNOME
• lightdm

windows

I found the solution:

xdotool getwindowfocus windowclose