An information processing device comprising: (a) a display (103, 104) that displays one or more windows; (b) a controller that controls the display so as to control display of the windows by the display and a layout of the windows; and (c) a storage that stores a history of the layout of the windows that is displayed on the display, (d) wherein the controller comprises: a window controller that generates one or more candidates of the layout of the windows based on the history of the layout of the windows; and a display controller (206, 209) that causes the display to display the candidates generated by the window controller, (e) the window controller issues an instruction to the display controller to display the windows in a layout selected from the candidates displayed on the display, wherein the window controller selects one of the candidates of the layout based on the accumulated counts a user manipulated when each window display layout candidate is displayed on the display and (f) the display controller (206, 209) causes the windows to be displayed in the selected layout according to the instruction from the window controller, (g) the windows include: a main window that displays processing details of a main application; and a pair window that displays processing details of a pair application that is activated by the main application, (h) the storage stores a position of the main window in association with a position of the pair window when either one of the position of the main window and the position of the pair window is changed, (i) the window controller, when the main application is newly activated, sets a combination of a position of the main window that displays processing details of the main application and a position of the pair window associated with the position of the main window as the candidates of the layout of the windows among the layouts included in the history stored in the storage, and (j) the display (103, 104) displays the main window and the pair window in the layout indicated by the selected candidate of the layout. (a) a display (103, 104) that displays one or more windows; (b) a controller that controls the display so as to control display of the windows by the display and a layout of the windows; and (c) a storage that stores a history of the layout of the windows that is displayed on the display, (d) wherein the controller comprises: a window controller that generates one or more candidates of the layout of the windows based on the history of the layout of the windows; and a display controller (206, 209) that causes the display to display the candidates generated by the window controller, a window controller that generates one or more candidates of the layout of the windows based on the history of the layout of the windows; and a display controller (206, 209) that causes the display to display the candidates generated by the window controller, (e) the window controller issues an instruction to the display controller to display the windows in a layout selected from the candidates displayed on the display, wherein the window controller selects one of the candidates of the layout based on the accumulated counts a user manipulated when each window display layout candidate is displayed on the display and (f) the display controller (206, 209) causes the windows to be displayed in the selected layout according to the instruction from the window controller, (g) the windows include: a main window that displays processing details of a main application; and a pair window that displays processing details of a pair application that is activated by the main application, a main window that displays processing details of a main application; and a pair window that displays processing details of a pair application that is activated by the main application, (h) the storage stores a position of the main window in association with a position of the pair window when either one of the position of the main window and the position of the pair window is changed, (i) the window controller, when the main application is newly activated, sets a combination of a position of the main window that displays processing details of the main application and a position of the pair window associated with the position of the main window as the candidates of the layout of the windows among the layouts included in the history stored in the storage, and (j) the display (103, 104) displays the main window and the pair window in the layout indicated by the selected candidate of the layout.