Description
Previously when opening the right sidebar (settings panel) a classname is-sidebar-opened was added to the dom. This allowed developers to know when that sidebar was opened and target the editor with styles. Right now it seems like the right sidebar has a fixed width of 280px (references to const SIDEBAR_WIDTH = 280; in the JS code). It's not clear how developers can adjust this width to be a % rather than a fixed width. The sidebar is far too narrow for our needs. In WordPress 6.5 and previous versions we were able to set the editor width to 60% and the sidebar to 40%. Then using the is-sidebar-opened class we could change the editor to 100% so there wasn't empty space. Without that classname, or ability to edit the width of the sidebar we're stuck with an empty 40% width div.
I'm not sure when or why this behavior changed, but I found this: https://github.com/WordPress/gutenberg/pull/62237/files related PR that seems like it might be removing the class name.
Step-by-step reproduction instructions
-
Add a new page
-
Open the right sidebar
-
Observe the class named is-sidebar-opened is visible in WordPress 6.5 and earlier
-
The width property was previously in CSS
-
Add a new page
-
Opened the right sidebar
-
Observe the class named is-sidebar-opened is gone.
-
The width property is now inline hard coded to the divs
Screenshots, screen recording, code snippet
WordPress 6.5 and earlier

WordPress 6.6 Beta

Environment info
Bug Report
Description
Describe the bug.
Environment
- WordPress: 6.6-beta2
- PHP: 8.1.23
- Server: Apache/2.4.43 (Unix)
- Database: mysqli (Server: 5.7.28 / Client: mysqlnd 8.1.23)
- Browser: Chrome 125.0.0.0 (macOS)
- Plugins:
- Advanced Custom Fields PRO 6.3.1.2
- Query Monitor 3.16.3
- WordPress Beta Tester 3.5.5
Please confirm that you have searched existing issues in the repo.
Yes
Please confirm that you have tested with all plugins deactivated except Gutenberg.
Yes
Description
Previously when opening the right sidebar (settings panel) a classname
is-sidebar-openedwas added to the dom. This allowed developers to know when that sidebar was opened and target the editor with styles. Right now it seems like the right sidebar has a fixed width of 280px (references to const SIDEBAR_WIDTH = 280; in the JS code). It's not clear how developers can adjust this width to be a % rather than a fixed width. The sidebar is far too narrow for our needs. In WordPress 6.5 and previous versions we were able to set the editor width to 60% and the sidebar to 40%. Then using theis-sidebar-openedclass we could change the editor to 100% so there wasn't empty space. Without that classname, or ability to edit the width of the sidebar we're stuck with an empty 40% width div.I'm not sure when or why this behavior changed, but I found this: https://github.com/WordPress/gutenberg/pull/62237/files related PR that seems like it might be removing the class name.
Step-by-step reproduction instructions
Add a new page
Open the right sidebar
Observe the class named
is-sidebar-openedis visible in WordPress 6.5 and earlierThe width property was previously in CSS
Add a new page
Opened the right sidebar
Observe the class named
is-sidebar-openedis gone.The width property is now inline hard coded to the divs
Screenshots, screen recording, code snippet
WordPress 6.5 and earlier

WordPress 6.6 Beta

Environment info
Bug Report
Description
Describe the bug.
Environment
Please confirm that you have searched existing issues in the repo.
Yes
Please confirm that you have tested with all plugins deactivated except Gutenberg.
Yes