validation - Primefaces datatable validate all rows not only selected -

i have problem jsf , primefaces page. when try submit form validate rows not selected. think bug because should validate rows selected.

<h:form id="yearplanapproveform" styleclass="row col-md-12">     <p:messages id="messages"  autoupdate="true" closable="true" />     <p:datatable id="ypchangedt" widgetwar="ypchangedt"         value="#{yearplanprocessformc.yearplanapproveformuim.phoplanchangelist}"         selection="#{yearplanprocessformc.yearplanapproveformuim.phoplanchangelistselected}"         filteredvalue="#{yearplanprocessformc.yearplanapproveformuim.phoplanchangelistfiltered}"         rowkey="#{ypchange.phoplanchangehistory.id}" var="ypchange"         tablestyle="width:auto"         rowsperpagetemplate="5,10,15,50,100" rows="15" paginator="true"          paginatorposition="bottom"         paginatortemplate="{currentpagereport}  {firstpagelink} {previouspagelink} {pagelinks} {nextpagelink} {lastpagelink} {rowsperpagedropdown}"         emptymessage="#{msg['pho.no.data.found']}"         >         <p:column exportable="false" selectionmode="multiple" style="width:40px;text-align:center"></p:column>          <p:column headertext="response" style="width:15%">             <h:inputtext id="denydescripton" required="true" requiredmessage="required input!"              style="width:100%" value="#{ypchange.phoplanchangehistory.denydescription}" >         </h:inputtext>         <p:message for="denydescripton" id="test1234"/>         </p:column>     </p:datatable>      <h:panelgrid columns="3">         <h:panelgroup>             <p:commandbutton id="saveaction"                 update=":ypvalidatedt :aha:processcounter"                 action="#{yearplanprocessformc.save}" styleclass="btn btn-save"                 value="save"></p:commandbutton>             <p:message for="saveaction"></p:message>         </h:panelgroup>         <h:panelgroup>             <p:commandbutton id="deleteaction"                 update=":aha:processcounter"                  action="#{yearplanprocessformc.delete}" styleclass="btn btn-save"                 value="delete"></p:commandbutton>             <p:message for="deleteaction"></p:message>         </h:panelgroup>      </h:panelgrid>