Here is my code:
\documentclass{article}
\usepackage{pgfplots}
\usetikzlibrary{shadows.blur}
\begin{document}
\tikzfading[name=fade down,
top color=transparent!30,
bottom color=transparent!0]
\begin{tikzpicture}
\begin{axis}[axis x line*=bottom,
axis y line*=left, blur shadow]
\addplot[yshift=-2pt,ybar, blue, fill,path fading=fade down, rounded corners=2pt]
coordinates{(1,2.9) (2,1.7) (3,4.2) (4,5.1) (5,4) (6,2.2)};
\end{axis}
\end{tikzpicture}
\end{document}
when I compile the code use pdflatex, the PDF is display correct. but when I compile using xelatex, in the generated pdf, the shadows became to black color.
why? how to fix it?

