Canvas shows error when trying to build page through Canvas.

I am also having exactly this error, and the same workaround works here., thank you Oren.

This was working for me from install until recently. Unfortunately I both recently did an update and also installed and removed the "radix" theme due to pretty much all of their dependencies carrying serious warnings, so I'm not sure what broke it. Radix depended on components module which I hoped might be the problem, but I uninstalled and removed components as well and the problem persists. So if it is the problem, it's some config change it made and not in the code.

Thanks for reporting this!

Could you narrow down which block is hitting this problem? The code you commented out is necessary: just commenting it out is going to cause other problems. (Linking the issue that introduced that particular implementation).

Also, it looks like "UI Icons for Menu" module makes canvas to crash too.

How, exactly?

Steps to produce

• Installing a fresh Drupal CMS instance with the Mercury theme
• enabling Webform access
• edit main page and select to edit the header or open the library components menu shows error

An unexpected error has occurred while rendering the component's form.

Error 500: Drupal\Core\Render\Element::isEmpty(): Argument #1 ($elements) must be of type array, null given, called in /var/www/html/web/modules/contrib/canvas/src/Plugin/Canvas/ComponentSource/BlockComponent.php on line 245

I uninstalled (but did not remove) Webform Access and uncommented that code again, and this has apparently solved the problem for me for now. Thanks bdh676.