First: sorry or my english. And yes, it is exactly so: with activated “custom Sidebars plugin”, the new widget build area is broken AND the plugin did not work anymore. But when you install the “Classic Widgets” Plugin, everything works like in the older WP-versions. But then, you did not get the new Gutenberg-widget area, only the old widget area.
I have too problem when yesterday setup new 5.8 WP
New wigets in last 5.8 Wp looks terrible and all Forbidden. Its terrible for looking and use. This problem desappear with “Classic widgets” plugin.
I dont like new wigets style, I do not want use “Gutenberg” newer, thats because I use “Classic editor” plugin.
I Hate “gutenberg”, hate new widgets – its make not usable my wp.
I love old WP versions and “Elenentor”.
Thats because I love WP!
I also noticed this issue –
Custom Sidebars plugin is NOT compatible with the new widgets edit screen (powered by Gutenberg).
Install the official Classic Widgets plugin if you want to continue using it.
Also, we checked the widget area is showing a blank(no widgets) page. Please suggest.
I have the same problem, but everything seems ok with the Classic Widgets plugin,
I think the Classic Widget Plugin may be a short term solution,
If someone finds a way to still create custom sidebars and use the new Gutenberg editor at the same time, I’ll be glad to hear about it !