AssertionError: The container was serialized.

UPDATE: This only seems to happen, when drupal/storybook is enabled as well - I added it to the steps to reproduce.

I digged through the code a little more to track down this issue and I think I got it: the getInfo() implementation defines its callbacks like this:

 '#process' => [[$this, 'populateOptions']],
 '#element_validate' => [[$this, 'validateExistingComponent']],
 '#submit' => [[$this, 'submitForm']],

Using $this here results in the element class itself (and all its injected dependencies) being added to the element info array, which at last gets serialized before being written to cache.

Tomorrow, I'll create an issue fork that contains the necessary changes to rewrite all those callbacks to static - which is also how core does it in all its form element plugins.

Please see the issue fork for the fix. While fixing this issue, I also realized, that there was a submitForm callback registered, which is not defined in the ComponenSelectorElement, so I removed that one completely from the element information.

And I think I even found the cause, why this issue only happens when cl_editorial and storybook module are both installed: The storybook module provides a custom Drupal\storybook\Cache\SkippableBackend cache backend when development mode is enabled for that module - and this seems to result in the serialization error... but I am still confused, why this happens when re-installing a site from config, but maybe someone else has an idea, if maybe something has to be fixed at the storybook module as well?!

Any news on this? Because this prevents a site from being installed with both the cl_editorial and storybook module initially enabled.

I wonder if we could solve this by just adding use DependencySerializationTrait; to the class. Any chance you can try that?

That was the first thing I tried, when identifying the issue with the form element, but it does not fix the error, because the container itself still gets serialized due to $this usage in the getInfo() implementation (because all its information gets serialized when written to cache).

As I already mentioned: ALL core elements use the static approach instead of using $this, so this should be done with this element as well - and of course to avoid these errors ;)