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.