Treat windows or at least window identities as first class objects.

 Store window identities in variables, compare them for equality.
 Provide examples of performing some of the following:
 hide, 
 show, 
 close, 
 minimize, 
 maximize, 
 move,     and 
 resize a window. 


The window of interest may or may not have been created by your program.




nb=NotebookCreate[]; (*Create a window and store in a variable*)
nb===nb2 (*test for equality with another window object*)
SetOptions[nb,Visible->False](*Hide*)
SetOptions[nb,Visible->True](*Show*)
NotebookClose[nb] (*Close*)
SetOptions[nb,WindowMargins->{{x,Automatic},{y,Automatic}}](*Move to x,y screen position*)
SetOptions[nb,WindowSize->{100,100}](*Resize*)