Primefaces Drag&Drop drags and drops only one element from dataTable - primefaces

Question

So, I've used example from showcase of PrimeFaces https://www.primefaces.org/showcase/ui/dnd/dataTable.xhtml. That's my code:
<div class="page_content">
<div class="header">Очередь рассылок</div>
<script type="text/javascript">
function handleDrop(event, ui) {
var droppedEmail = ui.draggable;
droppedEmail.fadeOut('fast');
}
</script>
<h:form>
<p:fieldset id="availableEmailsField" legend="Доступные рассылки">
<p:dataTable id="availableEmails" var="email" value="#{emailingQueueUI.customEmails}">
<p:column style="width: 20px;">
<h:outputText id="dragIcon" styleClass="ui-icon ui-icon-arrow-4"/>
<p:draggable for="dragIcon" revert="true" helper="clone"/>
</p:column>
<p:column headerText="ID">
<h:outputText value="#{email.id}"/>
</p:column>
<p:column headerText="Название">
<h:outputText value="#{email.name}"/>
</p:column>
<p:column headerText="Заголовок">
<h:outputText value="#{email.header}"/>
</p:column>
<p:column headerText="Количество порции">
<h:outputText value="#{email.chunkSize}"/>
</p:column>
</p:dataTable>
</p:fieldset>
<p:outputPanel id="selectedEmailsField">
<p:outputPanel id="dropArea">
<h:outputText value="Переместите сюда c доступных рассылок" rendered="#{empty emailingQueueUI.customEmailQueue}" style="font-size:16px;" />
<p:dataTable id="selectedEmails" var="email" value="#{emailingQueueUI.customEmailQueue}" rendered="#{not empty emailingQueueUI.customEmailQueue}"
rowIndexVar="index">
<!--<p:ajax event="rowReorder" listener="#{emailingQueueUI.onQueueReorder}" update=":form" />-->
<p:column headerText="Номер в очереди">
<h:outputText value="#{index}"/>
</p:column>
<p:column headerText="Рассылка">
<h:outputText value="#{email.id}"/>
</p:column>
<p:column headerText="Название">
<h:outputText value="#{email.name}"/>
</p:column>
<p:column headerText="Заголовок">
<h:outputText value="#{email.header}"/>
</p:column>
<p:column headerText="Количество порции">
<h:outputText value="#{email.chunkSize}"/>
</p:column>
</p:dataTable>
</p:outputPanel>
</p:outputPanel>
<p:droppable for="selectedEmailsField" tolerance="touch" activeStyleClass="ui-state-highlight" datasource="availableEmails" onDrop="handleDrop">
<p:ajax listener="#{emailingQueueUI.onEmailDrop}" update="dropArea availableEmails" />
</p:droppable>
</h:form>
</div>
There is a problem with d&d, I can drag and drop only one element from "availableEmailsField". When I try to drop another element it removes previous element and adds the dropped one.

Answer 1

I think the problem is in your bean.
Make sure that you initialize customEmailQueue inside #PostConstruct method and use the proper bean scope. In this case #ViewScoped.

Answer 2

It seems that an update function must be setted correctly in order to work properly. I faced the same issue and discovered that the ajax inside dropable has to update all drag-drop area elements, it seems that this action solves the issue.
The solution that worked is to put inside your form an:
<h:panelGroup id="elementsPanel">
....
...
...
...
....
</h:panelGroup>
, surrounding all drag-drop elements (if you dont want a panelgroup the idea is to update all the components)
and on the dropable update this panel:
<p:droppable id="dropHandler" for="selectedTable" tolerance="touch" activeStyleClass="ui-state-highlight" datasource="myDataSource" onDrop="handleDrop">
<p:ajax listener="#{dimensionsClass.onDimensionDrop2}" update="elementsPanel" />
</p:droppable>
I hope that helps!