What is this thing?

In Photoshop, when you click inside the area to the right of the zoom % box, this box pops up.



That a histogram? I have no clue. Hasn't proven useful to me yet.

shows how the page size looks like in print??....
no idea, but i think that's what its for

Yeah. Thats the only thing I can find it has a relation to. Not to print size, I don't think, but just some sort of visual width/height measurement.

Yeah, because it does show you an idea of what your canvas is shaped like. If you change your canvas from a square to a rectangle, it reflects it in that little box, and shows you where the center is. In as much as I tried to click on that little box to change something, I could not.

I'm pretty sure it shows the size of your present document relative to the size you have set for page setup in your print dialogue.

Then again, it might just be a line drawing of a very simple, yet clever mousetrap.

hold control/ or ALT (I forget which on the PC) and click it and see what you get.