What Éric describes seems to match what I see on Precise.
I'd like to add that, when I drag a window to the top of the small monitor, the orange highlight indicates that it will be maximised on that (small) monitor, but when I release the mouse, the window jumps to the large monitor. So the code that produces the orange window-will-go-here rectangle behaves how I want, at least.
For expected behaviour, I'd agree with Éric, except that if I drag a window to the top, it should maximise to the screen my mouse is on. This is how smaller windows already behave.
What Éric describes seems to match what I see on Precise.
I'd like to add that, when I drag a window to the top of the small monitor, the orange highlight indicates that it will be maximised on that (small) monitor, but when I release the mouse, the window jumps to the large monitor. So the code that produces the orange window-will-go-here rectangle behaves how I want, at least.
For expected behaviour, I'd agree with Éric, except that if I drag a window to the top, it should maximise to the screen my mouse is on. This is how smaller windows already behave.