SYNOPSIS
void ModifyWindowProps(struct Window *window,
unsigned long hpos, unsigned long vpos,
unsigned long hrange, unsigned long vrange,
unsigned long hbody, unsigned long vbody)
DESCRIPTION
To resize the window sliders, call `ModifyWindowProps()'. This
receives the same three sets of parameters that
`ModifyEmbossedProp()' receives (position, range, and body.)