"Show Desktop" does not minimize anything. What really happens is a full screen, borderless, explorer window, opens on top of everything.
You can use.
Winkey + M to minimize all
Winkey + shift + M to restore all
Or
Copy and paste the following into a text file and save it as ShowDesktop.vbs. Then create a new shortcut linked to this file.
Set Shell = CreateObject ("Shell.Application")
Shell.MinimizeAll
Set Shell = Nothing
and
Copy and paste the following into a text file and save it as RestoreAll.vbs. Then create a new shortcut linked to this file.
Set Shell = CreateObject ("Shell.Application")
Shell.UndoMinimizeAll
Set Shell = Nothing