Instead there is a button on the window that when pushed will move the window to the front unless it already is the topmost window. If the window already is topmost, it will be moved behind all other windows. All rendering except the window border is done by views. Each view has it's own graphical environment and it's own coordinate system. Each view can have child views that have a coordinate system relative to it's parent.
Views are also responsible for handling user input from keyboard and mouse.