diff --git a/core/modules/workspace/src/FormOperations.php b/core/modules/workspace/src/FormOperations.php
index d660ea6..95d6c87 100644
--- a/core/modules/workspace/src/FormOperations.php
+++ b/core/modules/workspace/src/FormOperations.php
@@ -65,10 +65,7 @@ public function formAlter(array &$form, FormStateInterface $form_state, $form_id
 
     // Add an additional validation step for every form if we are in a
     // non-default workspace.
-    $form['#validate'][] = [$this, 'validateForm'];
-    foreach (Element::children($form['actions']) as $action) {
-      $form['actions'][$action]['#validate'][] = [$this, 'validateForm'];
-    }
+    $this->addWorkspaceValidation($form);
 
     // If a form has already been marked as safe or not to submit in a
     // non-default workspace, we don't have anything else to do.
@@ -93,9 +90,28 @@ public function formAlter(array &$form, FormStateInterface $form_state, $form_id
   }
 
   /**
+   * Adds our validation handler recursively on each element of a form.
+   *
+   * @param array &$element
+   *   An associative array containing the structure of the form.
+   */
+  protected function addWorkspaceValidation(array &$element) {
+    // Recurse through all children and add our validation handler if needed.
+    foreach (Element::children($element) as $key) {
+      if (isset($element[$key]) && $element[$key]) {
+        $this->addWorkspaceValidation($element[$key]);
+      }
+    }
+
+    if (isset($element['#validate'])) {
+      $element['#validate'][] = [$this, 'validateDefaultWorkspace'];
+    }
+  }
+
+  /**
    * Validation handler which sets a validation error for all unsupported forms.
    */
-  public function validateForm(array &$form, FormStateInterface $form_state) {
+  public function validateDefaultWorkspace(array &$form, FormStateInterface $form_state) {
     if ($form_state->get('workspace_safe') !== TRUE) {
       $form_state->setError($form, $this->t('This form can only be submitted in the default workspace.'));
     }