A handheld computer is provided that includes a first module and at least a second module. The first module includes a processor and a display. The second module is slideably coupled to the first module so that it functions as a sliding cover that may effectively change the visible area of the underlying display. The handheld computer includes a sensing device coupled to the processor. The sensing device provides information to the processor regarding the relative position of the first module with respect to the second module. The information provided may be used to reconfigure the visual output of the display or to select a macro command presented on the display.