Borders not shown in Firefox with border-collapse on table, position: relative on tbody, or background-color on cell

Just ran into this issue and came to a css only solution: just add background-clip: padding-box to your td element.

See this article for more information: https://developer.mozilla.org/en-US/docs/CSS/background-clip

This looks like a Firefox bug to me. The backgrounds are painting over the borders; you can see it if you use a translucent background color.

I filed https://bugzilla.mozilla.org/show_bug.cgi?id=688556

Just to put all in one place.

The problem is produced when you have a cell with position relative inside a table with collapsed borders (as Boris indicated and filled in the bug https://bugzilla.mozilla.org/show_bug.cgi?id=688556)

This can be easily solved using CSS as indicated by user2342963 (Adding background-clip: padding-box to the cell).

You can see the problem (with Firefox) and the fix here: http://jsfiddle.net/ramiro_conductiva/XgeAS/

table {border-spacing: 0px;}
td {border: 1px solid blue; background-color: yellow; padding: 5px;}
td.cellRelative {position: relative;}
td.cellRelativeFix {background-clip: padding-box;}
table.tableSeparate {border-collapse: separate;}
table.tableCollapse {border-collapse: collapse;}

<table class="tableSeparate">
    <tbody>
        <tr>
            <td class="cellRelative">position: relative</td>
            <td>position: static</td>
        </tr>
    </tbody>
</table>
<table class="tableCollapse">
    <tbody>
        <tr>
            <td class="cellRelative">position: relative</td>
            <td>position: static</td>
        </tr>
    </tbody>
</table>
<table class="tableCollapse">
    <tbody>
        <tr>
            <td class="cellRelative cellRelativeFix">position: relative</td>
            <td>position: static</td>
        </tr>
    </tbody>
</table>