Message-driven bean "loses" MDB icon and status

Question

Using JDev v11.1.1.5.0, when I create a MDB in my project using the wizard, it initially is displayed with the MDB icon next to it (a little envelope with a paperclip). However, about a second later, the icon changes to a normal 'Java' icon (coffee cup). I've also noticed that the MDB class does NOT appear in the Project Properties | EJB Module | Annotated EJB 3.0 Classes list box. The net result is that when the application is deployed, the MDB doesn't get registered to listen, so it never receives JMS messages.
I tried creating a new application from scratch, and created the exact same MDB. In this application, the icon 'sticks', and the class DOES show up in the "Annotated EJB 3.0 Classes" list box in the Project Properties dialog. (And, it will correctly register to receive JMS message on deployment.)
So, obviously something is different/wrong with my actual application that is preventing it from recognizing that the MDB class is an MDB. But, I don't know what. I've looked at all the settings in the Project Properties, looked at the actual project's .jpr file, etc., and can't see anything that would cause one application to not recognize MDBs.
Does anyone have any suggestions on how to figure out why my MDB classes aren't recognized as such in the one Application?
Here's the class I'm trying to use:
package com.acme;
import javax.ejb.MessageDriven;
import javax.jms.Message;
import javax.jms.MessageListener;
@MessageDriven(mappedName = "acme.DefaultQueue")
public class MessageEJB implements MessageListener {
    public void onMessage(Message message) {
         // ... code here ...
Thanks,
Karl

Answer 1

For those that might have this problem down the road, here's what I found... It seems that there was a corrupt "cache" file or something in the project. Specifically, I had to delete the files in the <app_name>\<project_name>\classes\.data\00000000 folder. Once I deleted those files (mostly .jdb files), and restarted JDeveloper, the correct icon displayed next to my MDB classes, AND they also showed up correctly in the Project Properties | EJB Console pane.
I'm not sure what these files are, but I assume they are cache files and get re-created automatically by JDeveloper when needed. I hope this helps someone else that has the same problem!