$second = open_floating_window({ background_color => '#00ff00' }); # window 11
$third = open_floating_window({ background_color => '#0000ff' }); # window 12
$second = open_floating_window({ background_color => '#00ff00' }); # window 11
$third = open_floating_window({ background_color => '#0000ff' }); # window 12