Program: 96365
Project: 96365
Buggy source:
/** 
 * {@inheritDoc}
 */
public void handleEvent(Event event){
  Display display=event.display;
  display.removeFilter(SWT.MouseDown,this);
  display.removeFilter(SWT.MouseEnter,m_highlightAppender);
  m_highlightAppender.removeAddedListeners();
  event.doit=false;
  event.type=SWT.None;
  Widget selectedWidget=event.widget;
  IComponentIdentifier compId=null;
  if (!(selectedWidget instanceof FigureCanvas)) {
    sendIdInfo(compId);
    return;
  }
  FigureCanvas figureCanvas=(FigureCanvas)selectedWidget;
  Composite parent=figureCanvas;
  while (parent != null && !(parent.getData(Startup.GD_GEF_VIEWER_DATA_KEY) instanceof GraphicalViewer)) {
    parent=parent.getParent();
  }
  if (parent == null) {
    sendIdInfo(compId);
    return;
  }
  Object gefData=parent.getData(Startup.GD_GEF_VIEWER_DATA_KEY);
  if (gefData instanceof EditPartViewer) {
    EditPartViewer viewer=(EditPartViewer)gefData;
    Point cursorLocation=new Point(display.map(null,viewer.getControl(),display.getCursorLocation()));
    EditPart editPart=viewer.findObjectAt(cursorLocation);
    EditPart primaryEditPart=FigureCanvasUtil.getPrimaryEditPart(editPart,viewer.getRootEditPart());
    List idStringList=Collections.EMPTY_LIST;
    if (primaryEditPart != null) {
      idStringList=getPathToRoot(viewer.getRootEditPart(),cursorLocation,primaryEditPart);
    }
 else {
      EditDomain editDomain=viewer.getEditDomain();
      if (editDomain != null) {
        PaletteViewer paletteViewer=editDomain.getPaletteViewer();
        if (paletteViewer != null) {
          EditPart paletteEditPart=paletteViewer.findObjectAt(new Point(display.map(viewer.getControl(),paletteViewer.getControl(),cursorLocation.getSWTPoint())));
          if (paletteEditPart != null) {
            idStringList=getToolPathToRoot(paletteViewer.getRootEditPart(),paletteEditPart);
          }
        }
      }
    }
    compId=createCompId(idStringList);
  }
  sendIdInfo(compId);
}

Fixed version (ground truth):
/** 
 * {@inheritDoc}
 */
public void handleEvent(Event event){
  Display display=event.display;
  display.removeFilter(SWT.MouseDown,this);
  display.removeFilter(SWT.MouseEnter,m_highlightAppender);
  m_highlightAppender.removeAddedListeners();
  event.doit=false;
  event.type=SWT.None;
  Widget selectedWidget=event.widget;
  IComponentIdentifier compId=null;
  if (!(selectedWidget instanceof FigureCanvas)) {
    sendIdInfo(compId);
    return;
  }
  FigureCanvas figureCanvas=(FigureCanvas)selectedWidget;
  Composite parent=figureCanvas;
  while (parent != null && !(parent.getData(Startup.TEST_GEF_VIEWER_DATA_KEY) instanceof GraphicalViewer)) {
    parent=parent.getParent();
  }
  if (parent == null) {
    sendIdInfo(compId);
    return;
  }
  Object gefData=parent.getData(Startup.TEST_GEF_VIEWER_DATA_KEY);
  if (gefData instanceof EditPartViewer) {
    EditPartViewer viewer=(EditPartViewer)gefData;
    Point cursorLocation=new Point(display.map(null,viewer.getControl(),display.getCursorLocation()));
    EditPart editPart=viewer.findObjectAt(cursorLocation);
    EditPart primaryEditPart=FigureCanvasUtil.getPrimaryEditPart(editPart,viewer.getRootEditPart());
    List idStringList=Collections.EMPTY_LIST;
    if (primaryEditPart != null) {
      idStringList=getPathToRoot(viewer.getRootEditPart(),cursorLocation,primaryEditPart);
    }
 else {
      EditDomain editDomain=viewer.getEditDomain();
      if (editDomain != null) {
        PaletteViewer paletteViewer=editDomain.getPaletteViewer();
        if (paletteViewer != null) {
          EditPart paletteEditPart=paletteViewer.findObjectAt(new Point(display.map(viewer.getControl(),paletteViewer.getControl(),cursorLocation.getSWTPoint())));
          if (paletteEditPart != null) {
            idStringList=getToolPathToRoot(paletteViewer.getRootEditPart(),paletteEditPart);
          }
        }
      }
    }
    compId=createCompId(idStringList);
  }
  sendIdInfo(compId);
}