A first computing device for controlling a second computing device, the first computing device comprising a processor; a display; a user input in the form of a pointer; and a data link for connecting said first and second computing devices. The display displays image data from said second computing device within a window that is smaller than said display. The processor is configured to determine that said pointer has left said window; responsive to determining said pointer has left said window, determine an intersection point on an edge of said window, said intersection point being a location at which the pointer left said window; determine whether said intersection point is within a threshold distance from a nearest corner of said window; and responsive to determining said intersection point is within said threshold distance, output a message to said second computing device that said pointer is positioned on said nearest corner.