Primefaces Tree - node is not right-clicked

I migrated to version 5.1 of Primefaces and now when I right click to open ContextMenu the node is not selected . In version 5.0 it worked correctly.

<h:form>
  <p:tree id="plano" value="#{planoMB.plano}" var="p" selectionMode="single" selection="#{planoMB.selectedNode}">
    <p:treeNode type="movto" icon="ui-icon-document">
      <h:outputText value="#{p.descricao}" />
    </p:treeNode>
  </p:tree>
  <p:contextMenu>
    <p:menuitem value="Editar" update=":editPlano" oncomplete="PF('dlgEditPlano').show()"/>
  </p:contextMenu>                    
</h:form>