reRender not working after DB is changed

[bossy]

Hello,

I have two tables with a many-to-many relationship (Building(buildId,buildName)
and Features(featId,feaName)). The implementation is via a link table.

I add/remove features to a building entity using the following page:

<h:panelGrid columns="2" rowClasses="prop"  width="100%" >
          <s:div><a:form styleClass="association" id="featuresChildren" >
                         
               <rich:dataTable id="featuresTable"  value="#{buildingHome.features}" var="_features" >
                                 
                   <rich:column sortBy="#{_features.featCodeDisplayText}">
                       <f:facet name="header">Building Features</f:facet>
                       <h:outputText value="#{_features.featCodeDisplayText}"/>
                   </rich:column>
                   
                   <rich:column >
                       <a:commandLink value="Remove" 
                             id="removeFeat" action="#{buildingFeaturesHome.removeFeature()}"  >     
                               <f:param name="featCode" value="#{_features.featCode}"/>
                              <a:support event="oncomplete" reRender="featuresTable" />
                        </a:commandLink>
                   </rich:column>
                   
               </rich:dataTable>                    
          </a:form></s:div>
 
          <s:div><a:form id="buildingFeatures" styleClass="edit" >               
                    <s:decorate id="featCodeField" template="layout/edit.xhtml">
                        <ui:define name="label">Features</ui:define>
                        <h:selectOneMenu value="#{buildingFeaturesHome.instance.id.featCode}">
                           <s:selectItems value="#{featuresList.resultList}" var="_f" label="#{_f.featCodeDisplayText}" 
                                     itemValue="#{_f.featCode}"  />                            
                      </h:selectOneMenu>               
                    </s:decorate>
                               
                    <a:commandLink  id="save" value="Add"  action="#{buildingFeaturesHome.addFeature()}"  >
                           <f:param name="featCode" value="#{buildingFeaturesHome.instance.id.featCode}"/>
                       <a:support event="oncomplete" reRender="featuresTable" />
                    </a:commandLink>                               
          </a:form></s:div>         
     </h:panelGrid>

My  BuildingFeaturesHome class has the following two methods:

     @RequestParameter
     String featCode;

     public String removeFeature()
     {

          String ret="";
          this.setId(new BuildingFeaturesId(buildingHome.getInstance().getBuildId(),featCode));     
    ret=this.remove();
          buildingHome.getEntityManager().refresh(buildingHome.getInstance());
          return ret;
     }
     
     
     
     public String addFeature()
     {
          if(this.getInstance().getId().getFeatCode()==null) return "";
          
          if(this.isManaged())
          {
               this.setInstance(new BuildingFeatures(new BuildingFeaturesId(BuildingHome.getInstance().getBuildId(),this.getInstance().getId().getFeatCode())));
          }
          else
          {
               this.getInstance().getId().setBuildId(BuildingHome.getInstance().getBuildId());
          }
    String ret=this.persist();
          buildingHome.getEntityManager().refresh(buildingHome.getInstance());          
          return ret;
     }

     
     
     
     It all works fine with one exception - the refresh/reRender on the Delete commandLink does not refresh the list with the current features, although the DB is updated.
  There are some exceptions to this - before I add any new features during a conversation the refresh works. But even in this case when I delete the last feature - the refresh again does not work.
  I do realise that this has something to do with the managed/transient state of the entities, but I can't work out why the refresh/reRender is affected by this.

  Any help will be highly apreciated.

  Thanks.