Program: 168197
Project: 168197
Buggy source:
/** 
 * Sets up the buttons, the button fields must already be created before calling this method
 */
private void initializeButtons(){
  if (fAddButton != null) {
    fAddButton.addSelectionListener(new SelectionAdapter(){
      @Override public void widgetSelected(      SelectionEvent e){
        DirectoryDialog dlg=new DirectoryDialog(fAddButton.getShell(),SWT.OPEN);
        dlg.setText("String_Node_Str");
        boolean cannotExit=false;
        String path=null;
        while (!cannotExit) {
          path=dlg.open();
          if (path == null)           return;
 else {
            cannotExit=updateLocationTree(path);
            if (!cannotExit) {
              ErrorDialog.openError(dlg.getParent(),"String_Node_Str","String_Node_Str",new Status(IStatus.ERROR,CommonUiActivator.PLUGIN_ID,"String_Node_Str"));
            }
          }
        }
      }
    }
);
  }
  fAddFileButton.addSelectionListener(new SelectionAdapter(){
    @Override public void widgetSelected(    SelectionEvent e){
      FileDialog dlg=new FileDialog(fAddFileButton.getShell(),SWT.OPEN);
      dlg.setText("String_Node_Str");
      boolean cannotExit=false;
      String path=null;
      while (!cannotExit) {
        path=dlg.open();
        if (path == null)         return;
 else {
          cannotExit=updateLocationTree(path);
          if (!cannotExit) {
            ErrorDialog.openError(dlg.getParent(),"String_Node_Str","String_Node_Str",new Status(IStatus.ERROR,CommonUiActivator.PLUGIN_ID,"String_Node_Str"));
          }
        }
      }
    }
  }
);
  fRemoveButton.addSelectionListener(new SelectionAdapter(){
    @Override public void widgetSelected(    SelectionEvent e){
      handleRemove();
    }
  }
);
  fRemoveButton.setEnabled(true);
  updateButtons();
}

Fixed version (ground truth):
/** 
 * Sets up the buttons, the button fields must already be created before calling this method
 */
private void initializeButtons(){
  if (fAddButton != null) {
    fAddButton.addSelectionListener(new SelectionAdapter(){
      @Override public void widgetSelected(      SelectionEvent e){
        DirectoryDialog dlg=new DirectoryDialog(fAddButton.getShell(),SWT.OPEN);
        dlg.setText("String_Node_Str");
        boolean cannotExit=false;
        String path=null;
        while (!cannotExit) {
          path=dlg.open();
          if (path == null)           return;
 else {
            cannotExit=updateLocationTree(new String[]{path});
            if (!cannotExit) {
              ErrorDialog.openError(dlg.getParent(),"String_Node_Str","String_Node_Str",new Status(IStatus.ERROR,CommonUiActivator.PLUGIN_ID,"String_Node_Str"));
            }
          }
        }
      }
    }
);
  }
  fAddFileButton.addSelectionListener(new SelectionAdapter(){
    @Override public void widgetSelected(    SelectionEvent e){
      FileDialog dlg=new FileDialog(fAddFileButton.getShell(),SWT.OPEN | SWT.MULTI);
      dlg.setText("String_Node_Str");
      boolean cannotExit=false;
      String path=null;
      while (!cannotExit) {
        path=dlg.open();
        if (path == null)         return;
 else {
          cannotExit=updateLocationTree(dlg.getFileNames());
          if (!cannotExit) {
            ErrorDialog.openError(dlg.getParent(),"String_Node_Str","String_Node_Str",new Status(IStatus.ERROR,CommonUiActivator.PLUGIN_ID,"String_Node_Str"));
          }
        }
      }
    }
  }
);
  fRemoveButton.addSelectionListener(new SelectionAdapter(){
    @Override public void widgetSelected(    SelectionEvent e){
      handleRemove();
    }
  }
);
  fRemoveButton.setEnabled(true);
  updateButtons();
}