diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -5189,6 +5189,7 @@
       'PhabricatorApplicationTransactionInterface',
       'PhabricatorPolicyInterface',
       'PhabricatorFlaggableInterface',
+      'PhabricatorSubscribableInterface',
       'PhabricatorDestructibleInterface',
       'PhabricatorSpacesInterface',
     ),
diff --git a/src/applications/passphrase/controller/PassphraseCredentialViewController.php b/src/applications/passphrase/controller/PassphraseCredentialViewController.php
--- a/src/applications/passphrase/controller/PassphraseCredentialViewController.php
+++ b/src/applications/passphrase/controller/PassphraseCredentialViewController.php
@@ -193,6 +193,8 @@
         $viewer->renderHandleList($used_by_phids));
     }
 
+    $properties->invokeWillRenderEvent();
+
     $description = $credential->getDescription();
     if (strlen($description)) {
       $properties->addSectionHeader(
diff --git a/src/applications/passphrase/storage/PassphraseCredential.php b/src/applications/passphrase/storage/PassphraseCredential.php
--- a/src/applications/passphrase/storage/PassphraseCredential.php
+++ b/src/applications/passphrase/storage/PassphraseCredential.php
@@ -5,6 +5,7 @@
     PhabricatorApplicationTransactionInterface,
     PhabricatorPolicyInterface,
     PhabricatorFlaggableInterface,
+    PhabricatorSubscribableInterface,
     PhabricatorDestructibleInterface,
     PhabricatorSpacesInterface {
 
@@ -147,6 +148,23 @@
     return null;
   }
 
+
+/* -(  PhabricatorSubscribableInterface  )----------------------------------- */
+
+
+  public function isAutomaticallySubscribed($phid) {
+    return false;
+  }
+
+  public function shouldShowSubscribersProperty() {
+    return true;
+  }
+
+  public function shouldAllowSubscription($phid) {
+    return true;
+  }
+
+
 /* -(  PhabricatorDestructibleInterface  )----------------------------------- */
 
   public function destroyObjectPermanently(