UN-FullScreen a Stack?

[Scott Rossi]

OK, on OS X 10.11 I decided to see what happens when maximizing a stack.
The window went fullscreen and my script for repositioning controls works
great, but now the display is stuck in fullscreen mode.  How do I get the
view back to multi-window view?  Setting the width/height of the stack
resizes the stack but leaves a black OS backdrop in place and the display
remains set the fullscreen mode.  What's the command to un-fullscreen a
stack?

Thanks & Regards,

Scott Rossi
Creative Director
Tactile Media, UX/UI Design