This seems random and contra intuitive. The article is also confusing, containing a section on how to set a solid color as a background, while that is actually what causes the issue...
From the other workaround, ie edit this registry entry, the delay is directly related to some portion of the Windows session system timing out and switching to a different session.
I wonder what's actually going on though. I was hoping this was a link to Raymend Chen
The question remains why didn't Microsoft notice the problem at the time as to the programmer it should have been obvious. But then from experience I think I've answered that already.
BTW, I've still some old machines with Win 7 so I might experiment with it.
Somewhere in my archive I've still a pre-release beta which from your comment wouldn't be patched but I don't think I've sufficient enthusiasm or curiosity to install it from scratch. :-)
Do you have a link to the thing about the session system timing out ? Curious about how this works behind the hood even if it is patched (especially since sometimes windows bugs will rarely come back in very niche specific situations)