So far, we have been looking at graphical user interfaces as a set of panels embedded one into another. This is well reflected in the world of desktop utility programs composed of windows and subwindows containing mostly static content scattered throughout a large desktop area where the user can use a mouse pointer to move around windows or adjust their size.
However, this design doesn't correspond well with modern user interfaces that often try to minimize the area they occupy (because of either a small display size like with embedded and mobile devices or to avoid obscuring the main display panel like in games), at the same time providing rich content with a lot of moving or dynamically resizing items. Such user interfaces ...
