Fix/18582 z index for snackbar

[ajotka]

Description

Fix #18582 for Snackbar notices. It was showing up under the footer and under the horizontal scrollbar.

How has this been tested?

Tested locally, by manual tests.
Wordpress 5.3.0.
Steps:
I:

• Add normal block
• Click Save
• Snackbar is showing up properly.
  II:
• Add block which is more than 1920px
• Click save
• Snackbar is showing up properly.

Screenshots

Types of changes

• add z-index 35 for editor layout in z-index file
• add overflow-x: hidden for editor layout

Checklist:

• [+] My code is tested.
• [+] My code follows the WordPress code style.
• [+] My code follows the accessibility standards.
• [+] RWD checked.

[jasmussen]

Thank you so much for the pull request 🎉

While it does seem to address the issue specifically, I left some comments to suggest we might need a different approach. Best I can tell the way you solved it here was to forcibly remove the horizontal scrollbar and change the z-index to be above any such scrollbars. But while I agree horizontal scrollbars are the worst (:D) every once in a while they are intentional, so we can't hide those.

All the snackbars are inside a container though, that you may be able to target instead, such as components-snackbar-list.

Thanks again for the PR!

[jasmussen]

If the goal is to fix the snackbar position, I would consider changing the z-index of components-snackbar-list rather than the content container itself. It might have adverse effects otherwise.

Unfortunately this particular classname also changed in a recent refactor in #18044, so it no longer exists in master.

[jasmussen]

I don't think we should add this. While we haven't seen it yet, there may be cases where you need to be able to scroll horizontally in the layout content. Most of the time the horizontal scrollbar is helpful to discover accidental horizontal scrollbars, i.e. when content is too wide, but you could even imagine a horizontally scrolling theme! :) https://wordpress.com/theme/shelf

[youknowriad]

I think this is already fixed in master, right?

[paaljoachim]

I am closing this PR. As the issue has been fixed.

[gwwar]

Thanks @ajotka for giving this a try!

In trunk I see the footer set to z-index 90 and the snackbar container set to 100000, with the same z-index stacking context so we should be good with current behavior

[ajotka]

This PR is from 2019 and you fixed it in different branch a long time ago, but never closed it ;) Thanks!