Since I upgraded to PGF 2.10, some of my arrows drawn with to don't look right anymore. For instance, they are missing arrow-heads, and some other styles I applied to them have also disappeared. For example:
\begin{tikzpicture}
\draw (0,0) to[->, line width=2mm] (3,1);
\end{tikzpicture}

I'm not getting any error messages nor anything relevant in the log file. This example compiles correctly with PGF 2.00.

