Comment 10 for bug 343575

I use the xdotool with the following script to simulate super+space in screen 0:

# find root in screen 0
xdotool search --maxdepth 0 --screen 0 "" windowfocus || exit 1

# pause, otherwise keys would be lost!
sleep 0.25

# send super+space
xdotool key --clearmodifiers super+space