VISIO::BUTTON
(int grid, int xpos, int ypos, int xsize, int ysize, string
caption)
Description: Creates a
button on grid 'grid' with coordinates 'xpos' and 'ypos'. The width
of the button is determined by 'xsize' and the height by 'ysize'.
Finally a text 'caption' is placed on the button. Returns the ID of the
created button.
Example: button
= VISIO::BUTTON (grid, 1, 1, 3, 1, "Exit")