static JPanel gridLayoutPanel_trackWidth_evenlySpacedCols(final int cols) {

  ret customLayoutPanel_trackWidth(func(Container parent) {

    int gap = 10;

    Dimension size = parent.getSize();

    int w = max(100, size.width)-gap*2;

    int y = gap;

    LL<Component> rows = groupInFixedSizeRows(parent.getComponents(), cols);

    new L<Int> colWidths;

    for i to cols:

      colWidths.add((i+1)*w/cols-i*w/cols);

    for (L<Component> row : rows) {

      int h = 0, x = gap;

      for (Component c : row) h = max(h, c.getPreferredSize().height);

      for i over row: {

        row.get(i).setBounds(x, y, colWidths.get(i)-gap, h);

        x += colWidths.get(i);

      }

      y += h + gap;

    }

    ret componentsBoundingSize(parent, gap);

  });

}