NAME
        NewModifyProp -- modifyprop(), but with selective refresh.

    SYNOPSIS
        NewModifyProp( gadget, window, requester, flags,
                       A0      A1      A2         D0
                HorizPot, VertPot, HorizBody, VertBody, NumGad )
                D1        D2       D3         D4        D5

        VOID NewModifyProp( struct gadget *, struct window *,
                struct requester *, uword, uword, uword, uword, uword, word );

    FUNCTION
        Performs the function of modifyprop(), but refreshes
        gadgets in the list as specified by the NumGad parameter.
        With NumGad = -1, this function is identical to modifyprop().

        New for V36: When NumGad = 1, this function will now perform
        an incremental update of the proportional gadget knob image,
        rather than refreshing the entire gadget.  This means much
        less flashing when programmatically scrolling a proportional
        gadget.

    INPUTS
        PropGadget = pointer to a proportional gadget
        window = pointer to the window containing the gadget or the window
            containing the requester containing the gadget.
        requester = pointer to a requester (may be null if this isn't
            a requester gadget)
        Flags = value to be stored in the Flags field of the propinfo
        HorizPot = value to be stored in the HorizPot field of the propinfo
        VertPot = value to be stored in the VertPot field of the propinfo
        HorizBody = value to be stored in the HorizBody field of the propinfo
        VertBody = value to be stored in the VertBody field of the propinfo
        NumGad = number of gadgets to be refreshed after propgadget internals
            have been adjusted.  -1 means "to end of list."

    RESULT
        None

    BUGS

    SEE ALSO 
        modifyprop()
        The Intuition Reference Manual contains more information on
        Proportional Gadgets.