load_TV_button(wid.i2.v, button_row.i4.v, button_column.i4.v,
This function should only be called by functions which create objects
that are inherited from the TV_button object. It differs from
create_TV_button() only in that it does not allocate memory for the
structure. It is assumbed that the caller of _this function has already
allocated the memory that is needed.