<p:autoComplete> inside cell editable <p:dataTable> not invoking complete method - primefaces

Question

I have a dataTable which has cell editing and global filter capability:
<p:dataTable id="tbl01" value="#{userMappingBacking.staffList}" editable="true" editMode="cell" filteredValue="#{userMappingBacking.staffListFiltered}" var="s" rowKey="#{s.id}" widgetVar="tbl101WV">
...
<f:facet name="header">
<p:outputPanel>
<p:toolbar>
<p:toolbarGroup align="${text.line_start}">
<p:commandButton value="#{text.save}" action="#{userMappingBacking.saveChanges}" update="msgs"/>
</p:toolbarGroup>
<p:toolbarGroup align="${text.line_end}">
<h:outputText value="#{text.search_all_fields}:"/>
<p:spacer width="10"/>
<h:inputText id="globalFilter" onkeyup="PF('tbl101WV').filter()" />
</p:toolbarGroup>
</p:toolbar>
</p:outputPanel>
</f:facet>
...
<p:column headerText="#{text.user}" filterBy="#{s.userName}" filterable="false">
<p:cellEditor id="ceUser">
<f:facet name="output"><h:outputText value="#{s.userName}"/></f:facet>
<f:facet name="input">
<p:autoComplete id="acUser" dropdown="true" value="#{s.userName}" completeMethod="#{userMappingBacking.completeUnAssignedUser}"/>
</f:facet>
</p:cellEditor>
</p:column>
</p:dataTable>
and the backing bean userMappingBacking supports all the methods and works fine.
My problem is quite strange, the <p:autoComplete id="acUser"... doesn't invoke the complete method unless a filter is applied to the table, after a filter application every thing works fine, but before that no values are completed in the p:autoComplete.
Could any one help or give an insight into this.

Answer 1

I actually found the problem to be in the backing bean, I had 3 lists:
staffList = new ArrayList<>();
staffListFiltered = new ArrayList<>();
userDTOList = new ArrayList<>();
that I fill in a viewAction listener
public void loadStaffListAction() {
staffList = zaties.listAllStaff();
staffListFiltered = zaties.listAllStaff();
userDTOList = iacw.listAllUsers();
}
the problem was having 2 different lists staffList and staffListFiltered filled with different objects from the service, so changing the code like this:
public void loadStaffListAction() {
staffList = zaties.listAllStaff();
staffListFiltered = staffList;
userDTOList = iacw.listAllUsers();
}
and this solved the problem, nevertheless this is not the best practice, as explained below.
Common Error:
in the primefaces showcase for filtered datatable the never initialize the filteredValue list to any thing, they leave it as null so the datatable filter logic initialize it in the right way, paying attention to this detail I advise:
Don't initialize any thing unless you get an error.
comments are welcome!