I think the confusion may be the second click is doing what it would normally do in the case of "nothing being selected" which is "show what is hidden"....Then at that point you would select any of the hidden objects you want to show again and say done, and they appear in the whole scene again with the rest of the objects.

So the second click is not a "reversal" of what will be hidden. Paq's script can do the reversal, then use the hide command.