The follow-up on open sourcing the code was also unhelpful:
> Hey everybody asking that the source code be released: The source code was licensed from another company. If you want the source code, you have to go ask them.
Windows 7 came out in 2009, at least three years before candy crush.
> they're an OS developer and they can't spend a day figuring out a floating point bug?
Maybe it’s bad to argue by appeal to authority, but I take Raymond Chen’s side that it was a hard problem to debug in the time available over some internet sneering that it must have been easy, any day.
According to the link: they licensed the code and had access to it. But none of them wrote it and they couldn't justify the days of debugging that would be required when they had millions of other LOC to test and port.