Improve 267-regress-mark-restart.t
Improve 267-regress-mark-restart.t

Another window with a mark is needed for issue #2900.

stapelberg/i3,stapelberg/i3,Airblader/i3-original,cornerman/i3,Airblader/i3,stapelberg/i3,i3/i3,Airblader/i3-original,Airblader/i3,Airblader/i3-original,i3/i3,Airblader/i3,i3/i3,Airblader/i3-original,cornerman/i3,Airblader/i3-original,Airblader/i3,cornerman/i3,stapelberg/i3,cornerman/i3,i3/i3