function(p) p.type == 'row',
        grouped
      );

    local CalculateXforPanel(index, panel) =
      local panelsPerRow = std.floor(gridWidth / panel.gridPos.w);
      local col = std.mod(index, panelsPerRow);
      panel + { gridPos+: { x: panel.gridPos.w * col } };

    local panelsBeforeRowsWithX = std.mapWithIndex(CalculateXforPanel, panelsBeforeRows);

    local rowPanelsWithX =
      std.map(