The `instanceof Array` check for setGroups doesn't work in iframes so it messes up the array by nesting it: https://github.com/6pac/6pac.github.io/blob/master/SlickGrid/slick.dataview.js#L328 Should be replaced by Array.isArray or equivalent: http://perfectionkills.com/instanceof-considered-harmful-or-how-to-write-a-robust-isarray/