The close and back buttons on pop up windows are miles apart. Once you have clicked though several layers you get a mixture of close 'X' and back arrows on opposite sides of the screen. On my 32 inch monitor this is a long way to move the mouse when all I want to do is close all windows and go back to the initial window or search query.

Very petty I know but having a close all or common location to save scrolling around will make tasks just that little bit quicker and less infuriating.