>
nothing will change: Existing <tt>RooDataSet</tt>s and <tt>RooDataHist</tt>s
(that inherit from <tt>RooTreeData</tt>) can be read in <i>without problems</i> in
RooFit 3.00 and will be converted on the fly to the new dataset structure
in memory.
<br><br>
<i>User code that explicitly uses <tt>RooTreeData</tt> pointers should
be changed to <tt>RooAbsData</tt> pointers</i>. This change should be transparent
for all uses, with the exception of the <tt>RooTreeData::tree()</tt> method.
Explicit access to tree im