Not Display Action Rated 5 out of 5 stars

The "not display" key works only if I press it before hovering the thumbnail. What if I need to hide the maximized image with a key?
I use Shift to maximize image, I'd like to use that same key to hide it.

This review is for a previous version of the add-on (2.4).  This user has a previous review of this add-on.