Changing depth

Hey, i have this movieclip(see my signature), the squares are duplicated in a FOR loop, setting their depth 1 higher for every next square. but now i want a button to appear OVER all these squares, the button is just a static square drawn in the canvas, so not by actionscript. but even if i put this button in a layer above the layer where the original square is at, it gets placed UNDER the squares, what to do? (cant swap depth, cos there is nothing to swap it with…)
btw. Why is the depth of everything as standard always set to -16380 or something like that?