Multiple monitors and full screen

[dnomhcir]

I decided to test ctwm with multiple displays. I found that when I clicked the full screen button in netflix, it filled both monitors, so half of the picture was on the tv and half on the laptop which is connected to the tv. This isn't what happens with icewm. I don't know if this is a bug or whether the concept of full screen is open to interpretation. I am using google-chrome on debian 10.