You can’t position: sticky; a <thead>. Nor a <tr>. But you can sticky a <th>, which means you can make sticky headers inside a regular ol’ <table>. This is tricky stuff, because if you didn’t know this weird quirk, it would be hard to blame you. It makes way more sense to sticky a parent element like the table header rather than each individiaul element in a row. The issue boils down to the fact that stickiness requires position: relative…