I get this too, and I swear it's getting wider each time. It's not just this dialogue either. I get it when I close Workstation and I still have a guest running, the pop up asks whether to suspend etc. I have to drag all the way across a 4K screen and off the edge of another HD screen before I get to the accept button. Still exists in 15.0.3.
Not really the end of the world, but irritating enough I'm spending time Googling for it.