Program: 32599
Project: 32599
Buggy source:
/** 
 * Remove all customizations installed to various areas of the current UI in order to uninstall autocompletion support. This method is invoked after the comboBox's UI delegate is changed.
 */
private void undecorateOriginalUI(){
  if (this.arrowButton != null) {
    this.arrowButton.removeMouseListener(arrowButtonMouseListener);
    this.arrowButton.addMouseListener(arrowButtonMouseListener.getDecorated());
  }
  this.comboBox.getModel().removeListDataListener(listDataHandler);
  if (this.comboBox.getEditor() == comboBoxEditor)   this.comboBox.setEditor(comboBoxEditor.getDelegate());
  this.popupMenu.removePopupMenuListener(popupSizerHandler);
  this.popup.getList().removeMouseListener(popupMouseHandler);
  final ActionMap actionMap=comboBox.getActionMap();
  actionMap.put("String_Node_Str",originalSelectPreviousAction);
  actionMap.put("String_Node_Str",originalSelectNextAction);
  actionMap.put("String_Node_Str",originalSelectPrevious2Action);
  actionMap.put("String_Node_Str",originalSelectNext2Action);
  actionMap.put("String_Node_Str",originalAquaSelectPreviousAction);
  actionMap.put("String_Node_Str",originalAquaSelectNextAction);
  this.document.setDocumentFilter(null);
  this.comboBoxEditorComponent.removeKeyListener(strictModeBackspaceHandler);
  this.comboBoxEditorComponent.removeFocusListener(selectTextOnFocusGainHandler);
  if (this.comboBox.getRenderer() == renderer)   this.comboBox.setRenderer(originalRenderer);
  this.originalRenderer=null;
  this.comboBoxEditor=null;
  this.comboBoxEditorComponent=null;
  this.document=null;
  this.popupMenu=null;
  this.popup=null;
  this.arrowButton=null;
}

Fixed version (ground truth):
/** 
 * Remove all customizations installed to various areas of the current UI in order to uninstall autocompletion support. This method is invoked after the comboBox's UI delegate is changed.
 */
private void undecorateOriginalUI(){
  if (this.arrowButton != null) {
    this.arrowButton.removeMouseListener(arrowButtonMouseListener);
    this.arrowButton.addMouseListener(arrowButtonMouseListener.getDecorated());
  }
  this.comboBox.getModel().removeListDataListener(listDataHandler);
  if (this.comboBox.getEditor() == comboBoxEditor)   this.comboBox.setEditor(comboBoxEditor.getDelegate());
  this.popupMenu.removePopupMenuListener(popupSizerHandler);
  this.popupLocationFix.uninstall();
  this.popup.getList().removeMouseListener(popupMouseHandler);
  final ActionMap actionMap=comboBox.getActionMap();
  actionMap.put("String_Node_Str",originalSelectPreviousAction);
  actionMap.put("String_Node_Str",originalSelectNextAction);
  actionMap.put("String_Node_Str",originalSelectPrevious2Action);
  actionMap.put("String_Node_Str",originalSelectNext2Action);
  actionMap.put("String_Node_Str",originalAquaSelectPreviousAction);
  actionMap.put("String_Node_Str",originalAquaSelectNextAction);
  this.document.setDocumentFilter(null);
  this.comboBoxEditorComponent.removeKeyListener(strictModeBackspaceHandler);
  this.comboBoxEditorComponent.removeFocusListener(selectTextOnFocusGainHandler);
  if (this.comboBox.getRenderer() == renderer)   this.comboBox.setRenderer(originalRenderer);
  this.originalRenderer=null;
  this.comboBoxEditor=null;
  this.comboBoxEditorComponent=null;
  this.document=null;
  this.popupMenu=null;
  this.popup=null;
  this.arrowButton=null;
}