Problem/Motivation
I know there's another issue with a similar error but I believe this is a different issue.. Might be something to do with permissions. I have a roles which is quite restricted. When they login this error appears, but not for the administrator. What permission do users need to see/use image_popup?
I'm using the popup in a view that has a thumbnail in one of the table cells. I won't paste the entire trace .. but let me know if you need more:
Warning: Undefined array key "effects" in Drupal\image_popup\Plugin\Field\FieldFormatter\ImagePopupFieldFormatter->viewElements() (line 185 of modules/contrib/image_popup/src/Plugin/Field/FieldFormatter/ImagePopupFieldFormatter.php).
Drupal\image_popup\Plugin\Field\FieldFormatter\ImagePopupFieldFormatter->viewElements(Object, 'en') (Line: 89)
Drupal\Core\Field\FormatterBase->view(Object, 'en') (Line: 76)
Drupal\Core\Field\Plugin\Field\FieldFormatter\EntityReferenceFormatterBase->view(Object, NULL) (Line: 265)
Drupal\Core\Entity\Entity\EntityViewDisplay->buildMultiple(Array) (Line: 223)
Drupal\Core\Entity\Entity\EntityViewDisplay->build(Object) (Line: 461)
Drupal\Core\Entity\EntityViewBuilder->viewField(Object, Array) (Line: 243)
Drupal\Core\Field\FieldItemList->view(Array) (Line: 856)
Drupal\views\Plugin\views\field\EntityField->getItems(Object) (Line: 1151)
Drupal\views\Plugin\views\field\FieldPluginBase->advancedRender(Object) (Line: 238)
template_preprocess_views_view_field(Array, 'views_view_field', Array)
call_user_func_array('template_preprocess_views_view_field', Array) (Line: 287)
Drupal\Core\Theme\ThemeManager->render('views_view_field', Array) (Line: 422)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 201)
Drupal\Core\Render\Renderer->render(Array) (Line: 1747)
Drupal\views\Plugin\views\field\FieldPluginBase->theme(Object) (Line: 779)
Drupal\views\Plugin\views\style\StylePluginBase->elementPreRenderRow(Array)
call_user_func_array(Array, Array) (Line: 101)
Drupal\Core\Render\Renderer->doTrustedCallback(Array, Array, 'Render #pre_render callbacks must be methods of a class that implements \Drupal\Core\Security\TrustedCallbackInterface or be an anonymous function. The callback was %s. See https://www.drupal.org/node/2966725', 'exception', 'Drupal\Core\Render\Element\RenderCallbackInterface') (Line: 772)
Drupal\Core\Render\Renderer->doCallback('#pre_render', Array, Array) (Line: 363)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 201)
Drupal\Core\Render\Renderer->render(Array) (Line: 718)