Abstract: A document-processing device has a multi-window display function. This device displays an indicia which enables an operator to quickly and easily visually ascertain the positional and size relationship between a window and a window-movable region on an image screen where the window can move or change its size. The indicia includes a first display region, a first display pattern, a second display region, and a second display pattern. The first display pattern is displayed in the first display region. The second display pattern is displayed in the second display region. A ratio of the length of the first display pattern to that of the first display region is equal to the ratio of the length of the window to the length of the window-movable region. The ratio of a length of the second display pattern to that of the second display region is equal to a ratio of the width of the window to the width of the window-movable region.