I'm assuming. I've never actually tried the mutliplayer. I don't know anyone else who has it that plays it.
I'll have to see if I can launch it in a second window and cannot to myself like I can with Terraria.
The same supports multiple windows open at once. At least the non-steam version does. I ran a stand-alone server in a seperate window that I ran from the game client and opened a second window to connect to it.