A copy and paste operation allows selection from a copy source display area to be copied from a display screen of a display unit and pasted to a paste destination display area without losing the original appearance and style. A processing unit determines from data generated on the style of a copy source and data on the paste destination style, whether the paste destination style would change the copy source style. If it is determined that the paste destination style would change the copy source style, the copy source style is processed into the paste destination style in order to make the paste destination style consistent with the copy source style. The paste destination display area then displays the copy source display area pasted therein with the copy source style.