beamer block inside a tikz node ?

[Daniel Winkelmann]

I was trying to have a block be a node but the node is bigger than the
block.
How can I get the node to be the same size and use the same colors for text
an background?

{{\usebeamercolor[fg]{block title}\colorbox{bg}{Block title}}

takes care of the colors for the title but how can I use \usebeamercolor
with fill ?

any ideas ?

Daniel

\documentclass{beamer}
\usepackage{tikz}
\usetikzlibrary{calc,backgrounds,positioning}
\mode<presentation>
{
\usetheme{JuanLesPins}
\usecolortheme{seahorse}
\usecolortheme{rose} % lily, orchid, rose
\setbeamertemplate{blocks}[rounded][shadow=false]
}
\begin{document}
\begin{frame}
\begin{tikzpicture}[>=latex]
\node[text width=3cm,draw,rounded corners] (A) {%
\begin{block}{Block title}
\begin{itemize}
\item Frame doesn't fit block
\item Two
\end{itemize}
\end{block}
};
% defining a new style
\tikzstyle{block} = [rectangle, draw,fill=blue!10,text width=3cm, rounded
corners]
\node[block,draw,below=of A] (B) {{\usebeamercolor[fg]{block
title}\colorbox{bg}{Block title}}
\begin{itemize}
\item Background color not the same
\item Four
\end{itemize}
};
\draw[->] (A)--(B);
\end{tikzpicture}
\end{frame}
\end{document}