Program: 117948
Project: 117948
Buggy source:
private void fillUIBranches(final Project project,boolean lastUsedBranch) throws JSONException {
  final String storage=getStorage(project);
  if (LoginHelper.isRemoteConnection(getConnection())) {
    currentProjectSettings=project;
    final List<String> projectBranches=new ArrayList<String>();
    if ("String_Node_Str".equals(storage)) {
      projectBranches.add("String_Node_Str");
      branchesViewer.setInput(projectBranches);
      branchesViewer.setSelection(new StructuredSelection(new Object[]{"String_Node_Str"}));
    }
 else     if ("String_Node_Str".equals(storage)) {
      List<String> branches=getBranches(project);
      projectBranches.addAll(branches);
      branchesViewer.setInput(projectBranches);
      if (projectBranches.size() != 0) {
        branchesViewer.setSelection(new StructuredSelection(new Object[]{projectBranches.contains("String_Node_Str") ? "String_Node_Str" : projectBranches.get(0)}));
      }
    }
    branchesViewer.getCombo().setEnabled(false);
    if (backgroundGUIUpdate == null) {
      backgroundGUIUpdate=new Job("String_Node_Str"){
        @Override protected IStatus run(        IProgressMonitor monitor){
          projectBranches.clear();
          try {
            projectBranches.addAll(loginHelper.getProjectBranches(currentProjectSettings));
          }
 catch (          JSONException e) {
            ExceptionHandler.process(e);
          }
          return org.eclipse.core.runtime.Status.OK_STATUS;
        }
      }
;
      Job.getJobManager().addJobChangeListener(new JobChangeAdapter(){
        @Override public void done(        IJobChangeEvent event){
          if (event.getJob().equals(backgroundGUIUpdate)) {
            if (branchesViewer != null && !branchesViewer.getCombo().isDisposed()) {
              branchesViewer.getCombo().getDisplay().syncExec(new Runnable(){
                @Override public void run(){
                  if (branchesViewer == null || branchesViewer.getControl() == null || branchesViewer.getControl().isDisposed()) {
                    return;
                  }
                  branchesViewer.setInput(projectBranches);
                  if ("String_Node_Str".equals(storage) && projectBranches.size() != 0) {
                    branchesViewer.setSelection(new StructuredSelection(new Object[]{projectBranches.contains("String_Node_Str") ? "String_Node_Str" : projectBranches.get(0)}));
                  }
 else                   if ("String_Node_Str".equals(storage) && projectBranches.size() != 0) {
                    branchesViewer.setSelection(new StructuredSelection(new Object[]{projectBranches.contains("String_Node_Str") ? "String_Node_Str" : projectBranches.get(0)}));
                  }
                  branchesViewer.getCombo().setEnabled(projectViewer.getControl().isEnabled());
                }
              }
);
            }
          }
        }
      }
);
      branchesViewer.getCombo().addDisposeListener(new DisposeListener(){
        @Override public void widgetDisposed(        DisposeEvent e){
          backgroundGUIUpdate=null;
        }
      }
);
    }
    backgroundGUIUpdate.schedule();
  }
}

Fixed version (ground truth):
private void fillUIBranches(final Project project,boolean lastUsedBranch) throws JSONException {
  final String storage=getStorage(project);
  if (LoginHelper.isRemoteConnection(getConnection())) {
    currentProjectSettings=project;
    final List<String> projectBranches=new ArrayList<String>();
    if ("String_Node_Str".equals(storage)) {
      projectBranches.add("String_Node_Str");
      branchesViewer.setInput(projectBranches);
      branchesViewer.setSelection(new StructuredSelection(new Object[]{"String_Node_Str"}));
    }
 else     if ("String_Node_Str".equals(storage)) {
      String master="String_Node_Str";
      projectBranches.add(master);
      branchesViewer.setInput(projectBranches);
      if (projectBranches.size() != 0) {
        branchesViewer.setSelection(new StructuredSelection(new Object[]{projectBranches.contains(master) ? master : projectBranches.get(0)}));
      }
    }
    branchesViewer.getCombo().setEnabled(false);
    if (backgroundGUIUpdate == null) {
      backgroundGUIUpdate=new Job("String_Node_Str"){
        @Override protected IStatus run(        IProgressMonitor monitor){
          projectBranches.clear();
          try {
            projectBranches.addAll(loginHelper.getProjectBranches(currentProjectSettings));
          }
 catch (          JSONException e) {
            ExceptionHandler.process(e);
          }
          return org.eclipse.core.runtime.Status.OK_STATUS;
        }
      }
;
      Job.getJobManager().addJobChangeListener(new JobChangeAdapter(){
        @Override public void done(        IJobChangeEvent event){
          if (event.getJob().equals(backgroundGUIUpdate)) {
            if (branchesViewer != null && !branchesViewer.getCombo().isDisposed()) {
              branchesViewer.getCombo().getDisplay().syncExec(new Runnable(){
                @Override public void run(){
                  if (branchesViewer == null || branchesViewer.getControl() == null || branchesViewer.getControl().isDisposed()) {
                    return;
                  }
                  branchesViewer.setInput(projectBranches);
                  if ("String_Node_Str".equals(storage) && projectBranches.size() != 0) {
                    branchesViewer.setSelection(new StructuredSelection(new Object[]{projectBranches.contains("String_Node_Str") ? "String_Node_Str" : projectBranches.get(0)}));
                  }
 else                   if ("String_Node_Str".equals(storage) && projectBranches.size() != 0) {
                    branchesViewer.setSelection(new StructuredSelection(new Object[]{projectBranches.contains("String_Node_Str") ? "String_Node_Str" : projectBranches.get(0)}));
                  }
                  branchesViewer.getCombo().setEnabled(projectViewer.getControl().isEnabled());
                }
              }
);
            }
          }
        }
      }
);
      branchesViewer.getCombo().addDisposeListener(new DisposeListener(){
        @Override public void widgetDisposed(        DisposeEvent e){
          backgroundGUIUpdate=null;
        }
      }
);
    }
    backgroundGUIUpdate.schedule();
  }
}