private static void check(@NotNull RadContainer grid, final boolean isRow, final int cellIndex){
    if (!grid.getLayoutManager().isGrid()){
      throw new IllegalArgumentException("container must be grid");
    }

    final int cellCount = isRow ? grid.getGridRowCount() : grid.getGridColumnCount();
    if (cellIndex == 0 && cellCount == 0) return;
    if (cellIndex < 0 || cellIndex >= cellCount) {
      throw new IllegalArgumentException("invalid index: " + cellIndex);
    }
  }
private static void check(@NotNull RadContainer grid, final boolean isRow, final int cellIndex)