A window of a computer application on a display device is controlled through associating a pop-up window with the screen window of the computer application, wherein the computer application provides more than one screen window and a pop-up window is associated with each screen window of the computer application, and at least one mouse-sensitive area is defined for each screen window of the computer application, such that a mouse click on a mouse-sensitive area causes the appropriate pop-up window to be displayed on the display device.