AIUI Windows/386 2.x is basically a pre-emptive V86-mode DOS multitasker that happens to be running Windows as one of its tasks. So the GUI itself is cooperativ

AIUI Windows/386 2.x is basically a pre-emptive V86-mode DOS multitasker that happens to be running Windows as one of its tasks. So the GUI itself is cooperative, but between its VM and DOS VMs it can pre-empt. (Windows 3.x 386 mode is similar, with Windows 9x stuff in the Windows VM can pre-emptively multitask, mostly).