Desktop icons are not in Program Manager tree after Win + D "Hide Desktop"

Hi,

I would like to be sure, that this behavior is "by Design" in Windows 7 and 10. 

Reproducing steps for Windows 7, 10 :

1. Open notepad, for instance, to be sure that Win+D works.
2. Win + D. Notepad is minimized.
3. Get Program Manager tree via UI automation COM interface: there are no desktop icons list.
4. Win + D. Notepad is open.
5. Get Program Manager tree via UI automation COM interface: desktop icons list present.