A Scrollbar Appear in a right panel when editing a page or post

[Pratik Jain]

With WordPress 5.7 Beta 3, there is a scrollbar in right side panel when we add or edit any page or post.

The scrollbar appear only on Mozilla Browser. In Chrome Browser there is no scrollbar.

My Mozilla Browser version is 85.0.2

[Pratik Jain]

Scrollbar in Mozilla FireFox Browser

[mukesh27]

#52574 was marked as a duplicate.

[hellofromTonya]

Could not reproduce on Mac with latest 5.7 trunk version and Firefox 85.0.2

[audrasjb]

Could not reproduce on Mac/Firefox 85.0.2

[audrasjb]

I could not reproduce the issue as well.
Tested on MacOSX/Firefox 85.0.2.

[hellofromTonya]

Able to reproduce on Mac with Firegox 85.0.2 and latest 5.7 trunk version WHEN changing "System Preferences > General > Show scroll bars" to "Always".

[hellofromTonya]

• On Mac
• using Firefox 85.0.2
• Latest version of 5.7 from trunk

Not able to reproduce until I changed System Preferences > General > Show scroll bars to Always. After that change, then I can reproduce. See attached gifs.

[hellofromTonya]

After testing with @peterwilsoncc @audrasjb and @davidbaumwald, discovered:

• Can reproduce on Mac and Windows
• Happens in latest version of 5.7 trunk as well as in 5.6.1

As Peter notes

I am seeing it on 5.6.1 on my site, so not a 5.7 regression.

Removing trunk as the version.

As 5.7 RC1 is tomorrow, there's no patch, and not a 5.7 regression, moving it to a Future Release.

[dianeco]

I believe this is a 5.6 regression. Testing with Windows/Firefox 85.0.2, I can see a horizontal scrollbar with WP 5.7, which wasn't there with WP 5.6 (screenshot above).

[SergeyBiryukov]

Might be related: #52809

[sabernhardt]

#53486 was marked as a duplicate.

[janboddez]

Not a solution in the true sense, but this workaround (setting Firefox to use overlay scrollbars) seems to do the trick for me (on Windows 10): head over to about:config and add ui.useOverlayScrollbars with a (number) value of 1.

Source: ​https://www.reddit.com/r/gnome/comments/r2ne2f/til_overlay_scrollbars_in_firefox_and_thunderbird/

One downside is that sites with, e.g., overflow-y: scroll may have the scrollbar(s) move in front (and thus partially cover) certain page elements. (Chrome doesn’t do this.)

A potential actual fix would be to detect the presence of a vertical scrollbar and set an appropriate margin on the sidebar's child elements, in Firefox only, which seems super risky and not very future proof.