As a native U.S. speaker (also long in technology), I would balk just a little at the "at" there. I mean, I cannot call it wrong. But coming from what is common usage to me, I would expect to see "in" there, as a location where the button "resides."
I would expect "at" used in something more like: "Right clicking the 3 vertical dots (Kebab) button found at the top right hand corner, would launch this menu ..." And in that case, I could just as well expect "found in."
Meanwhile, "on" I would never use in this case. You may click "on" the button, but I would not find the button "on" the top right-hand corner. I might find a person leaning against a lamppost "on" a corner, because they are literally standing on it, but not on a screen in technology.
But also interesting to me here is that I had never yet heard of that button called a "kebab" before. :) I just call it the 3 dots or 3 vertical dots. When they are/were 3 short lines, I heard some call it a "burger" or a "sandwich," but I have a low tolerance for accepting that and I refuse to use it. :)