As a result, the amount of information, such as texts and images, displayed in a window W increases, while maintaining the position and size of each window W. [0078] On the other hand, when reducing display resolution (i.e., change from 2048???1536 dots (QXGA) to 1024???768 dots (XGA)), display conditions as shown in FIG. 5 are switched to those as shown in FIG. 4.