Block Plugin Derivatives Discovery I need some help with my code. I am creating blocks dynamically using the plugin derivatives. I store some form data in a database table, then I display it in each block separately, depending on it's derivative id. My issue is: while, I do obtain all the individual blocks on a full clear cache, in the "Place Block" section, it's not there when I submit the form, basically, I would like the form submit function to trigger the derivative creation and it's discovery. Any suggestions appreciated. 

Here's my Plugin Derivative code: 

&lt;?php

namespace Drupal\simpleads\Plugin\Derivative;

use Drupal\Component\Plugin\Derivative\DeriverBase;

class SimpleAdsBlock extends DeriverBase
{
    public function getDerivativeDefinitions($base_plugin_definition)
    {
        $query = \Drupal::database()
            -&gt;select('simpleads_blocks', 'sb')
            -&gt;fields('sb');
        $results = $query-&gt;execute()-&gt;fetchAll();

    foreach ($results as $result) {
        $this-&gt;derivatives[$result-&gt;bid] = $base_plugin_definition;
        $this-&gt;derivatives[$result-&gt;bid]['admin_label'] = $result-&gt;name;
    }

    return $this-&gt;derivatives;
    }
}
Copied from BlockContent::postSave():

// Invalidate the block cache to update custom block-based derivatives.
\Drupal::service('plugin.manager.block')-&gt;clearCachedDefinitions();