diff --git a/src/Form/BlockClassSettingsForm.php b/src/Form/BlockClassSettingsForm.php
index 1d1b05c..b8f7964 100644
--- a/src/Form/BlockClassSettingsForm.php
+++ b/src/Form/BlockClassSettingsForm.php
@@ -165,6 +165,13 @@ class BlockClassSettingsForm extends ConfigFormBase {
       '#title' => $this->t("Quantity of classes per block"),
       '#type' => 'number',
       '#default_value' => $qty_classes_per_block,
+      // Show the qty_classes_per_block only when the field type is multiple
+      // because is the only type that is used.
+      '#states' => [
+        'visible' => [
+          ':input[name="field_type"]' => ['value' => 'multiple_textfields'],
+        ],
+      ],
     ];
 
     $maxlength_block_class_field = 255;