diff --git a/src/Form/FacetForm.php b/src/Form/FacetForm.php
index a6188ba..4f7b77f 100644
--- a/src/Form/FacetForm.php
+++ b/src/Form/FacetForm.php
@@ -129,6 +129,9 @@ public function form(array $form, FormStateInterface $form_state) {
     foreach ($this->widgetPluginManager->getDefinitions() as $widget_id => $definition) {
       $widget_options[$widget_id] = !empty($definition['label']) ? $definition['label'] : $widget_id;
     }
+
+    // Filters all the available widgets to make sure that only those that
+    // this facet applies for are enabled.
     $widget_options = array_filter($widget_options, function ($widget_id) use ($facet) {
       $widget = $this->widgetPluginManager->createInstance($widget_id);
       return $widget->supportsFacet($facet);
@@ -182,8 +185,11 @@ public function form(array $form, FormStateInterface $form_state) {
       $all_processors = $form_state->get('processors');
     }
     $enabled_processors = $facet->getProcessors(TRUE);
+
+    // Filters all the available processors to make sure that only those that
+    // this facet applies for are enabled.
     $all_processors = array_filter($all_processors, function ($id) use ($facet) {
-      $processor = $this->processorPluginManager->createInstance($id);
+      $processor = $this->processorPluginManager->createInstance($id, ['facet' => $facet]);
       return $processor->supportsFacet($facet);
     }, ARRAY_FILTER_USE_KEY);
 
diff --git a/src/Processor/ProcessorInterface.php b/src/Processor/ProcessorInterface.php
index d5bef84..bd6f65a 100644
--- a/src/Processor/ProcessorInterface.php
+++ b/src/Processor/ProcessorInterface.php
@@ -111,6 +111,19 @@ public function isHidden();
    */
   public function getDescription();
 
+  /**
+   * Checks if the facet is supported by this widget.
+   *
+   * Reasons why this would be unsupported can be chosen by the widget.
+   *
+   * @param \Drupal\facets\FacetInterface $facet
+   *   The facet to check for.
+   *
+   * @return bool
+   *   Returns true when allowed, false otherwise.
+   *
+   * @see \Drupal\facets\Widget\WidgetPluginInterface::supportsFacet
+   */
   public function supportsFacet(FacetInterface $facet);
 
 }
diff --git a/src/Widget/WidgetPluginInterface.php b/src/Widget/WidgetPluginInterface.php
index c5028e5..cd90d4a 100644
--- a/src/Widget/WidgetPluginInterface.php
+++ b/src/Widget/WidgetPluginInterface.php
@@ -51,6 +51,19 @@ public function getQueryType(array $query_types);
    */
   public function isPropertyRequired($name, $type);
 
+  /**
+   * Checks if the facet is supported by this processor.
+   *
+   * Reasons why this would be unsupported can be chosen by the processor.
+   *
+   * @param \Drupal\facets\FacetInterface $facet
+   *   The facet to check for.
+   *
+   * @return bool
+   *   Returns true when allowed, false otherwise.
+   *
+   * @see \Drupal\facets\Processor\ProcessorInterface::supportsFacet
+   */
   public function supportsFacet(FacetInterface $facet);
 
   /**