[css-position][css-tables] Need to define relative positioning on table cells, rows and row groups in collapsing border model #11515
Description
https://drafts.csswg.org/css-position/#relpos-insets
https://drafts.csswg.org/css-tables/#border-collapsing
<!DOCTYPE html>
<style>td { border: 10px solid rgba(0, 0, 0, 0.5); background: cyan }</style>
<table style="border-collapse: collapse">
<td>A</td><td>B</td>
</table>
<table style="border-collapse: collapse">
<td>A</td><td style="position: relative; left: 0">B</td>
</table>
<table style="border-collapse: collapse">
<td>A</td><td style="position: relative; left: 50px">B</td>
</table>
<table style="border-collapse: collapse">
<tr style="position: relative; left: 50px">
<td>A</td><td>B</td>
</tr>
</table>
<table style="border-collapse: collapse">
<tbody style="position: relative; left: 50px">
<td>A</td><td>B</td>
</tbody>
</table>| Gecko | Blink | WebKit |
|---|---|---|
 |
 |
 |
It's surprising to say at least that adding position: relative on a cell shrinks the background area...