OK,
The new version is on the download page now. 1.1.8.5
You can specify the screen number now in options on the main tab.
The screen number is 0 based, so your primary display is 0, second display is 1, third display is 2. If you don't have enough screens it will display on the highest display number available. That is, if you specify display #2, but you only have 2 screens, it will display on #1 (the second one)
This way if you have two displays and set it to use the second one, but sometimes that screen is disabled, it will fall back automatically to the primary display.