I am often spotted lying on the floor or leaning over a ledge to get the right perspective and viewpoint for my shot. However, I try to keep on the roadway or sidewalk as gutters tend to have all sorts of noxious detritus coating its surface!
You have not only made a nice photograph but opened a portal of refreshing thought about what constitutes art for us. Essentially your post suggests, (and you are probably correct), that our presence (and whatever happens to be in front of the glass), in the street amounts to "performance art" when isolated, framed and appreciated by reflections in the shop windows.
In fact, this is a popular subject for photographers but, this is the first time, AFAIK, that anyone has called the displays "a gallery"! I like this as it give some form and boundaries to a section of photography related but distinct from street photography as it includes some of t
What's behind the glass blended with what's in the sky and street!
Thanks for this added clarity!
Asher