# Xephyr 
# Nested X server that runs as an X application.
# To ungrab mouse/keyboard; press ctrl+shift

# Run a nested X window, as display :1
Xephyr -br -ac -noreset -screen 800x600 :1

# Run a program on display :1
DISPLAY=:1 i3 

# Start a new X session with xinitrc
startx -- /usr/bin/Xephyr :1