Program: 81504
Project: 81504
Buggy source:
public void createControl(Composite parent){
  projectCombo=new Combo(parent,SWT.READ_ONLY);
  projectCombo.add("String_Node_Str");
  setControl(projectCombo);
  try {
    MantisRepositoryConnector connector=(MantisRepositoryConnector)TasksUi.getRepositoryManager().getRepositoryConnector(MantisCorePlugin.REPOSITORY_KIND);
    IMantisClient client=connector.getClientManager().getRepository(taskRepository);
    for (    MantisProject pd : client.getProjects())     projectCombo.add(pd.getName());
    projectCombo.setText(projectCombo.getItem(0));
    projectCombo.addSelectionListener(new SelectionListener(){
      public void widgetSelected(      SelectionEvent e){
        if (projectCombo.getSelectionIndex() > 0) {
          TaskAttribute attribute=taskData.getRoot().getAttribute(Key.PROJECT.getKey());
          attribute.setValue(projectCombo.getText());
          final MantisRepositoryConnector connector=(MantisRepositoryConnector)TasksUi.getRepositoryManager().getRepositoryConnector(MantisCorePlugin.REPOSITORY_KIND);
          try {
            getContainer().run(false,true,new IRunnableWithProgress(){
              public void run(              IProgressMonitor monitor) throws InvocationTargetException, InterruptedException {
                try {
                  MantisTaskDataHandler.createProjectSpecificAttributes(taskData,connector.getClientManager().getRepository(taskRepository),monitor);
                }
 catch (                MalformedURLException e) {
                  throw new InvocationTargetException(e);
                }
              }
            }
);
          }
 catch (          InvocationTargetException ex) {
            MantisUIPlugin.handleMantisException(ex);
            return;
          }
catch (          InterruptedException ex) {
            MantisUIPlugin.handleMantisException(ex);
            return;
          }
        }
        getWizard().getContainer().updateButtons();
      }
      public void widgetDefaultSelected(      SelectionEvent e){
      }
    }
);
  }
 catch (  Exception e1) {
    MantisCorePlugin.log(e1);
  }
}

Fixed version (ground truth):
public void createControl(Composite parent){
  Composite control=new Composite(parent,SWT.NONE);
  GridData gd=new GridData(SWT.FILL,SWT.FILL,false,false);
  control.setLayoutData(gd);
  GridLayout layout=new GridLayout(1,false);
  control.setLayout(layout);
  projectCombo=new Combo(control,SWT.READ_ONLY);
  projectCombo.add("String_Node_Str");
  setControl(projectCombo);
  try {
    MantisRepositoryConnector connector=(MantisRepositoryConnector)TasksUi.getRepositoryManager().getRepositoryConnector(MantisCorePlugin.REPOSITORY_KIND);
    IMantisClient client=connector.getClientManager().getRepository(taskRepository);
    for (    MantisProject pd : client.getProjects())     projectCombo.add(pd.getName());
    projectCombo.setText(projectCombo.getItem(0));
    projectCombo.addSelectionListener(new SelectionListener(){
      public void widgetSelected(      SelectionEvent e){
        if (projectCombo.getSelectionIndex() > 0) {
          TaskAttribute attribute=taskData.getRoot().getAttribute(Key.PROJECT.getKey());
          attribute.setValue(projectCombo.getText());
          final MantisRepositoryConnector connector=(MantisRepositoryConnector)TasksUi.getRepositoryManager().getRepositoryConnector(MantisCorePlugin.REPOSITORY_KIND);
          try {
            getContainer().run(false,true,new IRunnableWithProgress(){
              public void run(              IProgressMonitor monitor) throws InvocationTargetException, InterruptedException {
                try {
                  MantisTaskDataHandler.createProjectSpecificAttributes(taskData,connector.getClientManager().getRepository(taskRepository),monitor);
                }
 catch (                MalformedURLException e) {
                  throw new InvocationTargetException(e);
                }
              }
            }
);
          }
 catch (          InvocationTargetException ex) {
            MantisUIPlugin.handleMantisException(ex);
            return;
          }
catch (          InterruptedException ex) {
            MantisUIPlugin.handleMantisException(ex);
            return;
          }
        }
        getWizard().getContainer().updateButtons();
      }
      public void widgetDefaultSelected(      SelectionEvent e){
      }
    }
);
  }
 catch (  Exception e1) {
    MantisCorePlugin.log(e1);
  }
}