1531781 - borders and sticky position don't work in border-collapsed table head

Status: NEW

(Core :: Layout: Tables, enhancement, P3)

Description

[Axel Hecht [:Pike]]

Filing this rather specific, not sure if this is more general:

I have a position: sticky thead on https://l10n.allizom.org/shipping/dashboard?tree=fx_central.

That doesn't have borders between table cells. If I use devtools to switch position: sticky off, the borders are shown.

Tested on release and nightly.

Comment 1

[Emilio Cobos Álvarez (:emilio)]

(it's not clear to me how this should render given the borders are supposed to be collapsed)

Comment 2

[Emil Østergaard]

I have the same issue with some code I use at work. I seems like the borders of the thead gets stacked behind the background. This is also true for the th element.

Steps to recreate (ish)
If you take a look at @Alex Hechts link and puts a background: none on the table row containing the thead the border's will now be visible. Doing some testing locally has revealed that a change in the background opacity changes the visiblity of the borders. The more transparent the background, the more visible the borders become.

Comment 3

[Flaburgan]

This is a duplicate of https://bugzilla.mozilla.org/show_bug.cgi?id=1450584