1. A method of correlating a cursor position with displayed shapes in a computer system including storage means, means for displaying the shapes and a cursor, and user input means for moving the cursor and selecting a cursor position, said method comprising the steps of: displaying one or more shapes on the display means; determining a bounding rectangle of each displayed shape, and storing information representative of the shape and bounding rectangle; responsive to a user selecting a cursor position, determining a select region for said cursor position, said select region comprising a rectangle of picture elements surrounding said cursor position; examining the bounding rectangle of each displayed shape to determine whether it overlaps the select region; creating a bit map in the storage means corresponding to the select region; drawing each shape whose bounding rectangle overlaps the select region into the bit map; and examining the bit map to determine whether any shape has been written into the select region of the bit map, and if so correlating that shape with the cursor position selected by the user, wherein said steps of examining the bounding rectangle, drawing each shape, and examining the bit map are performed in succession for each shape.