    /**
     * @class Ext.selection.CheckboxModel
     */

    /**
     * @var {number}
     * The horizontal space before the checkbox
     */
    $checkbox-selection-model-cell-spacing-before: 5px !default;

    /**
     * @var {number}
     * The horizontal space after the checkbox
     */
    $checkbox-selection-model-cell-spacing-after: 5px !default;

    // private
    $checkbox-selection-model-column-header-padding:
        max(ceil(($grid-header-height - $form-checkbox-size) / 2), 0)
        $checkbox-selection-model-cell-spacing-after
        max(floor(($grid-header-height - $form-checkbox-size) / 2), 0)
        $checkbox-selection-model-cell-spacing-before;

    // private
    $checkbox-selection-model-cell-padding:
        max(ceil(($grid-row-height - $form-checkbox-size) / 2), 0)
        $checkbox-selection-model-cell-spacing-after
        max(floor(($grid-row-height - $form-checkbox-size) / 2), 0)
        $checkbox-selection-model-cell-spacing-before;