private boolean hideAutopopupIfMeaningless() {
    if (!myLookup.isLookupDisposed()
        && isAutopopupCompletion()
        && !myLookup.isSelectionTouched()
        && !myLookup.isCalculating()) {
      myLookup.refreshUi(true);
      final List<LookupElement> items = myLookup.getItems();

      for (LookupElement item : items) {
        if (!myLookup.itemPattern(item).equals(item.getLookupString())) {
          return false;
        }

        if (item.isValid()) {
          final LookupElementPresentation presentation = new LookupElementPresentation();
          item.renderElement(presentation);
          if (StringUtil.isNotEmpty(presentation.getTailText())) {
            return false;
          }
        }
      }

      myLookup.hideLookup(false);
      LOG.assertTrue(CompletionServiceImpl.getCompletionService().getCurrentCompletion() == null);
      CompletionServiceImpl.setCompletionPhase(new CompletionPhase.EmptyAutoPopup(this));
      return true;
    }
    return false;
  }
  public boolean addItem(LookupElement item, PrefixMatcher matcher) {
    LookupElementPresentation presentation = renderItemApproximately(item);
    if (containsDummyIdentifier(presentation.getItemText())
        || containsDummyIdentifier(presentation.getTailText())
        || containsDummyIdentifier(presentation.getTypeText())) {
      return false;
    }

    myMatchers.put(item, matcher);
    updateLookupWidth(item, presentation);
    synchronized (myList) {
      myArranger.addElement(this, item, presentation);
    }
    return true;
  }
  @Override
  public void addElement(
      Lookup lookup, LookupElement element, LookupElementPresentation presentation) {
    StatisticsWeigher.clearBaseStatisticsInfo(element);

    final String invariant =
        presentation.getItemText()
            + "###"
            + getTailTextOrSpace(presentation)
            + "###"
            + presentation.getTypeText();
    element.putUserData(PRESENTATION_INVARIANT, invariant);

    CompletionSorterImpl sorter = obtainSorter(element);
    Classifier<LookupElement> classifier = myClassifiers.get(sorter);
    if (classifier == null) {
      myClassifiers.put(sorter, classifier = sorter.buildClassifier(new AlphaClassifier(lookup)));
    }
    classifier.addElement(element);

    super.addElement(lookup, element, presentation);
  }
 @NotNull
 private static String getTailTextOrSpace(LookupElementPresentation presentation) {
   String tailText = presentation.getTailText();
   return tailText == null || tailText.isEmpty() ? " " : tailText;
 }