Alt-Esc and Z-order problem

Is this a Windows bug?

Alt-Esc a window --> goes to back of z-order
Alt-F4 (or click "x ") --> next window "flashes" (active) for moment --> BOTTOM window (prev sent to back) = now active (topmost)

Ie When close window, the alt-esc'ed window LOOPS ROUND back to top, instead of (correctly) going up from bottom just 1 (ie gradually making it's way back to top)

EDIT: Actually i've just stumbled accross the "keyshort" help file (in C:\Windows\Help), and in it says "ALT+ESC - Cycle through items in the order they were opened "
So i misunderstood the function of alt-esc .. i thght it sent current window to back of window heap (which is what i WANT it to do!)