@Nullable
  private Map<Integer, Usage> getSelectedUsages() {
    int[] rows = myResultsPreviewTable.getSelectedRows();
    Map<Integer, Usage> result = null;
    for (int i = rows.length - 1; i >= 0; i--) {
      int row = rows[i];
      Object valueAt = myResultsPreviewTable.getModel().getValueAt(row, 0);
      if (valueAt instanceof FindPopupItem) {
        if (result == null) result = new LinkedHashMap<>();
        result.put(row, ((FindPopupItem)valueAt).getUsage());
      }
    }
    return result;
  }
@Nullable
  private Map<Integer, Usage> getSelectedUsages()