Delete a row in datatable with confirmDialog - jsf-2

Question

My problem consists in deleting an item from data table. When i click on the button delete a confirm Dialog will appear to confirm removing the row from database. If so, the data will be removed but the data table isn't updated unless i logout and login and if i select another item it won't be even deleted.
<h:form id="form">
<p:panel id="panelform" header="Databases" >
<p:dataTable value="#{dataMB.customersDatas}" var="item" id="datas" rowsPerPageTemplate="5,10,15,20,25,30" paginator="true" rows="10" filteredValue="#{dataMB.filteredDatas}" selectionMode="single" rowKey="#{item.id}"selection="#{dataMB.selectedData}">
<p:ajax event="rowSelect" update=":form:dataView, :form:deleteButton, :form:viewButton" listener="#{dataMB.onRowSelect}"/>
</p:dataTable>
<p:panel>
<p:commandButton style="width: 8%;height: 100%" id="viewButton" value="View" oncomplete="dataDialogView.show()" disabled="#{dataMB.disabled}" icon="ui-icon-search" title="data details"/>
<p:commandButton style="width: 8%;height: 100%" id="deleteButton" value="Delete" oncomplete="deleteDialog.show()" disabled="#{dataMB.disabled}" icon="ui-icon-trash"/>
</p:panel>
</p:panel>
</h:form>
<p:confirmDialog style="position: absolute; width: 50px; border-color: blue" id="deleteData" message="Your Database Will be completely removed . Are you sure? " appendToBody="true" header="Delete Data" severity="alert" widgetVar="deleteDialog">
<h:form>
<p:commandButton id="confirm" style="width: 25%;height: 100%" value="Confirm" actionListener="#{dataMB.deleteData()}" update=":form:datas" ajax="true" oncomplete="deleteDialog.hide(); purchase.hide();" >
</p:commandButton>
<p:commandButton id="cancel" style="width: 25%;height: 100%" value="Later" onclick="deleteDialog.hide();" type="button" />
</h:form>
</p:confirmDialog>
deleteData() method in my sessionScoped managed Bean
public String deleteData() {
logger.log(Level.SEVERE, "*****delete Data***** ");
dataBusinessLocal.deleteData(selectedData);
return "datalist";
}

Answer 1

JSF is session based. To synchronize the state between client (browser) and server, JSF uses a hidden field javax.faces.ViewState. Right now, you are using two forms on the given page:
Clicking Action-Button on Form one
confirming on form two with updating the data table of form one
So, the hidden input field viewState isn't accurate any longer. Two ways I would possibly try:
Does the confirm-box have to be fancy JSF or does a javascript solution the job as well?
<p:commandButton id="deleteButton"
value="Delete"
disabled="#{dataMB.disabled}" icon="ui-icon-trash"
actionListener="#{dataMB.deleteData}"
onclick="if (!confirm('really delete?')) { return false;}" />
might do a similar job.
Possibility two: just rerender the whole form or the panel panelform instead of just the data table. This way a new javax.faces.ViewState should be rendered and the form works fine again.
Also, add a <h:messages /> somewhere in and update it on every step. In case there is a unexpected error, this might show it on the UI.
Hope that helps...