@NotNull
  private Pair<@Nls String, Icon> getPresentation(T t) {
    Pair<String, Icon> p = myPresentations.get(t);
    if (p == null) myPresentations.put(t, p = Pair.create(getDisplayName(t), getIcon(t)));
    return p;
  }
@NotNull
  private Pair<@Nls String, Icon> getPresentation(T t)