Pageflow-scoped bean "disappearing" during postbacks

Question

Hello,
I'm getting crazy with an error with a pageflow-scoped bean which suddenly "disappers"...
What I need to do is to use a bean to mantain the visibility status of 2 components (one is visible while the other isn't), an edit form and a warning message:
  <af:outputText value="some warning text"
                 visible="#{!pageFlowScope.untitled1.editFormViewable}"/>
  <af:panelFormLayout visible="#{pageFlowScope.untitled1.editFormViewable}">
  </af:panelFormLayout>the editFormViewable boolean variable is updated within the selectionListener of a tree (which also resides in the same bean), according to the node
selected by the user:
public class Untitled1Bean implements Serializable {
  private Boolean editFormViewable;
  public Untitled1Bean() { }
  public void treeSelectionListener(SelectionEvent event) {
    // manipulates editFormViewable
}so I either show the form or the warning message. I need to retain editFormViewable across requests so backingBean scope isn't fully appropriate, but I'm also in a bounded taskflow so according to the guide viewscope is not supported. So I went for pageFlow scope.
Here's the definition for the managed bean in my bounded taskflow:
    <managed-bean>
      <managed-bean-name>untitled1</managed-bean-name>
      <managed-bean-class>test.view.backing.Untitled1Bean</managed-bean-class>
      <managed-bean-scope>pageFlow</managed-bean-scope>
      <managed-property>
        <property-name>editFormViewable</property-name>
        <property-class>java.lang.Boolean</property-class>
        <value>false</value>
      </managed-property>
    </managed-bean>Now, when I enter the taskflow and load the page everything is fine, editFormViewable is correctly initialized to false (same if I set it to true) and the page displays correctly.
However, as soon as I expand a node of the tree to access its children, my app dies with the following exception:
javax.el.PropertyNotFoundException: Target Unreachable, 'untitled1' returned null
     at com.sun.el.parser.AstValue.getTarget(AstValue.java:88)
     at com.sun.el.parser.AstValue.invoke(AstValue.java:153)
     at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:283)
     at org.apache.myfaces.trinidad.component.UIXComponentBase.broadcastToMethodExpression(UIXComponentBase.java:1264)
     at org.apache.myfaces.trinidad.component.HierarchyUtils.__handleBroadcast(HierarchyUtils.java:81)
     at org.apache.myfaces.trinidad.component.UIXTree.broadcast(UIXTree.java:227)
     at oracle.adf.view.rich.component.rich.data.RichTree.broadcast(RichTree.java:220)
     at org.apache.myfaces.trinidad.component.UIXCollection.broadcast(UIXCollection.java:153)
     at org.apache.myfaces.trinidad.component.UIXTree.broadcast(UIXTree.java:231)
     at oracle.adf.view.rich.component.rich.data.RichTree.broadcast(RichTree.java:220)
     at oracle.adfinternal.view.faces.lifecycle.LifecycleImpl.broadcastEvents(LifecycleImpl.java:754)
     at oracle.adfinternal.view.faces.lifecycle.LifecycleImpl._executePhase(LifecycleImpl.java:282)
     at oracle.adfinternal.view.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:175)
     at javax.faces.webapp.FacesServlet.service(FacesServlet.java:265)
     at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
     at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
     at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:292)
     at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26)
     at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42)
     at oracle.adf.model.servlet.ADFBindingFilter.doFilter(ADFBindingFilter.java:181)
     at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42)
     at oracle.adfinternal.view.faces.webapp.rich.RegistrationFilter.doFilter(RegistrationFilter.java:85)
     ...So it seems that during postbacks on that page the managed bean is no longer accessibile? How can a pageFlow bean disappear at that point? The bounded taskflow only has a view activity with my page, I'm in, why is the bean getting instanced correctly and then lost?
Can someone please shed some light on this? I've used beans with scope longer than backing bean before, but never encountered such a problem.

Answer 1

Sorry but that can't be right, probably just a leftover from previous versions or a mistake in the doc.
JDeveloper itself on the "Managed Beans" tab of any taskflow, when registering a managed bean, presents you with a combobox offering 7 choices including pageFlow scope.
Why would JDeveloper offer a non-existant feature in its UI?
Also, I've used and seen them before. Check custRegBasicInformationBean, custRegDefineAddressesBean and welcomeUserRegistrationBean in FOD, they're pageflow-scoped beans and they do work.
Mine works too, except that it breaks completely on postbacks from a tree.