SQL*Graph LINEWIDTH problem

I have a problem with SQL*Graph. I'm using the following versions :

Kernel                  : 6.0.33.1.0.
SQL*Plus                : 3.0.6.4.1
SQL*Graph               : 1.1.13.2
Charting Library        : 1.0.24

Running the following script produces an unexpected result :

	SET LINEWIDTH THIN
	SELECT * FORM EMP;
	GRAPH SMOOTH LINE SAL BY EMPNO;

This script produces a line with LINEWIDTH = MEDIUM

When running the script a second time it produces a line with LINEWITDH = THIN How is this possible ?

Who can help me ?

Peter de Roo        Informatievoorziening & Automatisering    PTT Telecom
P.O.Box 188         9700AD Groningen                      The Netherlands
Internet: roo%ptt-iat_at_nluug.nl                  phone_at_desk: +31 50 855570