Created attachment 459789 [details]
Example HTML file showcasing the issue
When trying to absolute-position an element relative to the nearest `position: relative` table row (`tr`), it skips the `tr` and positions it relative to the next ancestor with `position: relative`.
In the example HTML file provided, it positions it relative to the document because there is no other ancestor with `position: relative`. Open this file in Safari, Chrome, and Firefox, and you'll see that Safari is the only one that has this issue.