Unable to start the game on a secondary monitor
There's no option to preconfigure what display the game goes fullscreen on, using a dual-display setup. On some games you can drag the shortcut for the game onto the desktop area of the secondary screen and it will start and go fullscreen on that display.
As a workaround I've tried to play in windowed mode and then drag the window onto my secondary display. In this situation the mouse cursor can escape the window and interact with other things (separate issue posted under darplaces.)
I think this suggestion/fix would be helpful for people who run a secondary "gaming display" like me.