Tell a field to be translatable I have a module with a plugin block. In the blockForm I create all the fields that I need for this block. In the CMS I realized that only the title of my block is translatable. I need some of my custom fields to be translatable. I just can't find how to do that.

public function blockForm($form, FormStateInterface $form_state){

    [...]

    $form['exit_link']['full_schedule_link'] = array(
      '#type' =&gt; 'textfield',
      '#title' =&gt; $this-&gt;t('Full Schedule Link'),
      '#description' =&gt; $this-&gt;t('Enter the schedule node, ex: (/node/20)'),
      '#default_value' =&gt; isset($this-&gt;configuration['full_schedule_link'])?    $this-&gt;configuration['full_schedule_link']:'',
      '#maxlength' =&gt; 256,
      '#size' =&gt; 64,
      '#weight' =&gt; '1',
      '#translatable' =&gt; true // &lt;-- NOT WORKING
    );

    [...]

}


Anyone has an idea how to do this?
You define that through the config schema, not the form.

See https://www.drupal.org/node/1905070, use type: label (weird know but that's how it is called) not string and type: text for textareas.

If you have no config schema yet, look at other modules providing blocks with configuration, like aggregator.module to see how to define that.