We'll consider this in the future when we update Spine for multi window support to better handle multiple monitors. Currently we'd have to reimplement the win+arrow functionality from scratch, as Windows doesn't provide it when the default title bar is not used.
You can shift+right click the Spine taskbar item to get the old style application context dialog, then choose Move. Next press any arrow key once, after that moving the mouse will cause the window to jump to where the mouse is. I agree it's a bit silly!
