public @NotNull List<NavigatableMessageElement> removeAllNavigatableMessagesInGroup(@NotNull String groupName) {
    synchronized (myLock) {
      List<NavigatableMessageElement> elements = myGroupNameToMessagesMap.get(groupName);
      if (elements == null) return Collections.emptyList();
      List<NavigatableMessageElement> removed = new ArrayList<>(elements);
      elements.clear();
      return removed;
    }
  }
public @NotNull List<NavigatableMessageElement> removeAllNavigatableMessagesInGroup(@NotNull String groupName)