[pstricks] mark zeros

[Doris Wagner]

hi list again,

the option markZeros of \psPolynomial seems to mark also the x- 
coordinate of the minimum of the following parabola. is that a bug?

\documentclass[12pt]{scrartcl}%pstricks
\textheight=27cm

\usepackage{pstricks}\usepackage{pst-func}

\begin{document}

\psset{unit=.7cm}
\begin{pspicture*}(-6,-7)(6,30)

\psaxes 
[arrowscale=2,Dx=5,dx=5,Dy=5,dy=5,linewidth=1.5pt,tickwidth=1.5pt]{->} 
(0,0)(-5.9,-6.9)(5.9,29.5)
\psset{dotsize=7pt}
\psPolynomial[markZeros,linecolor=blue,linewidth=2pt,coeff=-6 -1  
1,plotpoints=100]{-6}{6}

\end{pspicture*}

\end{document}