Unity: maximising window moves it to the next Desktop across
If a windowed window is near the left or right edge, clicking the "maximise" button will move it to the next workspace across.
I've no idea what the right or wrong answer is, but I was mightly confused about where my windows were going the first time I tried it.
They can of course be moved back to the first workspace by going to the workspace switcher button on the Launcher and faffing around.
My expectation is probably that the window should be maximised on to which over screen/workspace the actual maximise click occured *on*. The current unusual case of wishing to move workspace could still be done by moving the window to the other screen and then intentionally maximising it *on that window*.