# TikZ label do not display correctly anymore?

I upgraded my MiKTeX from 2.8 to 2.9 today. When I run my old code in this new system, I find it do not work well. label=90:$A$ and label=0+90:$A$ are displayed in two very differently ways! They were the same yesterday! This is just a stupid example, I want to write a \foreach sentence, such that the angles is a function. (Thanks for Hendrik Vogt)

\documentclass{article}% PDFLatex
\usepackage{tikz}

\begin{document}
\begin{tikzpicture}
\node[fill,label=90:$A$] at (0,0) (P0){};
\node[fill,label=-90:$A$] at (2,0) (P1){};
\node[fill,label=45:$A$] at (4,0) (P2){};
\node[fill,label=-45:$A$] at (6,0) (P3){};
\node[fill,label=0+90:$A$] at (0,2) (P4){};
\node[fill,label=0-90:$A$] at (2,2) (P5){};
\node[fill,label=0+45:$A$] at (4,2) (P6){};
\node[fill,label=0-45:$A$] at (6,2) (P7){};
\node[fill,label={45+45}:$A$] at (8,2) (P8){};
\end{tikzpicture}
\end{document}

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Welcome to tex.sx! A tip: If you indent lines by 4 spaces, then they're marked as a code sample. You can also mark the code and click the 'code' button (101010). –  Hendrik Vogt Dec 11 '10 at 9:02