In TeXShop LaTeX PDF preview window, sometimes when I double or triple click on the preview window I get this rectangle magnifier. I've seen in my friends Windows computer that this is a standard thing, but on TeXShop this seems to be some bug of some kind. My question is how can one get this rectangle magnifier in Macbook TeXShop TeXLive?
EDIT: Ha ok, but I think I actually just "found" out how to activate this, it almost works 100% of the time: I double press down on the Macbook trackpad. If I triple press then the larger rectangle magnifier appears and so on until all of the screen is magnified. Interesting.