[kristopolous]

overlapping windows was actually a challenging problem within the constraints of the old hardware.

[bonzini]

Actually it was due to legal worries that Windows 1 only supported tiling. In Windows 2 they ignored the worries and Apple promptly sued.

[technofiend]

There's a million links on that, this is one of the first with names and dates: http://www.folklore.org/StoryView.py?story=A_Rich_Neighbor_N...