@Override
  public ChangeListColumn<?> @NotNull [] getColumns() {
    Set<ChangeListColumn<?>> columns = new LinkedHashSet<>();
    for(AbstractVcs vcs: myBaseVcss) {
      CommittedChangesProvider<?, ?> provider = vcs.getCommittedChangesProvider();
      assert provider != null;
      ChangeListColumn[] providerColumns = provider.getColumns();
      for(ChangeListColumn col: providerColumns) {
        if (col == ChangeListColumn.DATE || col == ChangeListColumn.DESCRIPTION || col == ChangeListColumn.NAME ||
            col instanceof ChangeListColumn.ChangeListNumberColumn) {
          columns.add(col);
        }
      }
    }
    return columns.toArray(new ChangeListColumn[0]);
  }
@Override
  public ChangeListColumn<?> @NotNull [] getColumns()