diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
index 23c923dc25..4ade1636d7 100644
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -1487,6 +1487,7 @@ phutil_register_library_map(array(
     'ManiphestTaskDetailController' => 'applications/maniphest/controller/ManiphestTaskDetailController.php',
     'ManiphestTaskEditBulkJobType' => 'applications/maniphest/bulk/ManiphestTaskEditBulkJobType.php',
     'ManiphestTaskEditController' => 'applications/maniphest/controller/ManiphestTaskEditController.php',
+    'ManiphestTaskEditEngineLock' => 'applications/maniphest/editor/ManiphestTaskEditEngineLock.php',
     'ManiphestTaskFulltextEngine' => 'applications/maniphest/search/ManiphestTaskFulltextEngine.php',
     'ManiphestTaskGraph' => 'infrastructure/graph/ManiphestTaskGraph.php',
     'ManiphestTaskHasCommitEdgeType' => 'applications/maniphest/edge/ManiphestTaskHasCommitEdgeType.php',
@@ -2617,9 +2618,12 @@ phutil_register_library_map(array(
     'PhabricatorEditEngineConfigurationViewController' => 'applications/transactions/controller/PhabricatorEditEngineConfigurationViewController.php',
     'PhabricatorEditEngineController' => 'applications/transactions/controller/PhabricatorEditEngineController.php',
     'PhabricatorEditEngineDatasource' => 'applications/transactions/typeahead/PhabricatorEditEngineDatasource.php',
+    'PhabricatorEditEngineDefaultLock' => 'applications/transactions/editengine/PhabricatorEditEngineDefaultLock.php',
     'PhabricatorEditEngineExtension' => 'applications/transactions/engineextension/PhabricatorEditEngineExtension.php',
     'PhabricatorEditEngineExtensionModule' => 'applications/transactions/engineextension/PhabricatorEditEngineExtensionModule.php',
     'PhabricatorEditEngineListController' => 'applications/transactions/controller/PhabricatorEditEngineListController.php',
+    'PhabricatorEditEngineLock' => 'applications/transactions/editengine/PhabricatorEditEngineLock.php',
+    'PhabricatorEditEngineLockableInterface' => 'applications/transactions/editengine/PhabricatorEditEngineLockableInterface.php',
     'PhabricatorEditEnginePointsCommentAction' => 'applications/transactions/commentaction/PhabricatorEditEnginePointsCommentAction.php',
     'PhabricatorEditEngineProfileMenuItem' => 'applications/search/menuitem/PhabricatorEditEngineProfileMenuItem.php',
     'PhabricatorEditEngineQuery' => 'applications/transactions/query/PhabricatorEditEngineQuery.php',
@@ -6372,6 +6376,7 @@ phutil_register_library_map(array(
       'PhabricatorFulltextInterface',
       'DoorkeeperBridgedObjectInterface',
       'PhabricatorEditEngineSubtypeInterface',
+      'PhabricatorEditEngineLockableInterface',
     ),
     'ManiphestTaskAssignHeraldAction' => 'HeraldAction',
     'ManiphestTaskAssignOtherHeraldAction' => 'ManiphestTaskAssignHeraldAction',
@@ -6387,6 +6392,7 @@ phutil_register_library_map(array(
     'ManiphestTaskDetailController' => 'ManiphestController',
     'ManiphestTaskEditBulkJobType' => 'PhabricatorWorkerBulkJobType',
     'ManiphestTaskEditController' => 'ManiphestController',
+    'ManiphestTaskEditEngineLock' => 'PhabricatorEditEngineLock',
     'ManiphestTaskFulltextEngine' => 'PhabricatorFulltextEngine',
     'ManiphestTaskGraph' => 'PhabricatorObjectGraph',
     'ManiphestTaskHasCommitEdgeType' => 'PhabricatorEdgeType',
@@ -7679,9 +7685,11 @@ phutil_register_library_map(array(
     'PhabricatorEditEngineConfigurationViewController' => 'PhabricatorEditEngineController',
     'PhabricatorEditEngineController' => 'PhabricatorApplicationTransactionController',
     'PhabricatorEditEngineDatasource' => 'PhabricatorTypeaheadDatasource',
+    'PhabricatorEditEngineDefaultLock' => 'PhabricatorEditEngineLock',
     'PhabricatorEditEngineExtension' => 'Phobject',
     'PhabricatorEditEngineExtensionModule' => 'PhabricatorConfigModule',
     'PhabricatorEditEngineListController' => 'PhabricatorEditEngineController',
+    'PhabricatorEditEngineLock' => 'Phobject',
     'PhabricatorEditEnginePointsCommentAction' => 'PhabricatorEditEngineCommentAction',
     'PhabricatorEditEngineProfileMenuItem' => 'PhabricatorProfileMenuItem',
     'PhabricatorEditEngineQuery' => 'PhabricatorCursorPagedPolicyAwareQuery',
diff --git a/src/applications/maniphest/config/PhabricatorManiphestConfigOptions.php b/src/applications/maniphest/config/PhabricatorManiphestConfigOptions.php
index 9d692b539e..4a1927c5a8 100644
--- a/src/applications/maniphest/config/PhabricatorManiphestConfigOptions.php
+++ b/src/applications/maniphest/config/PhabricatorManiphestConfigOptions.php
@@ -210,6 +210,8 @@ The keys you can provide in a specification are:
   - `claim` //Optional bool.// By default, closing an unassigned task claims
     it. You can set this to `false` to disable this behavior for a particular
     status.
+  - `locked` //Optional bool.// Lock tasks in this status, preventing users
+    from commenting.
 
 Statuses will appear in the UI in the order specified. Note the status marked
 `special` as `duplicate` is not settable directly and will not appear in UI
diff --git a/src/applications/maniphest/constants/ManiphestTaskStatus.php b/src/applications/maniphest/constants/ManiphestTaskStatus.php
index eeeb4cf165..5734892f0a 100644
--- a/src/applications/maniphest/constants/ManiphestTaskStatus.php
+++ b/src/applications/maniphest/constants/ManiphestTaskStatus.php
@@ -156,6 +156,10 @@ final class ManiphestTaskStatus extends ManiphestConstants {
     return !self::isOpenStatus($status);
   }
 
+  public static function isLockedStatus($status) {
+    return self::getStatusAttribute($status, 'locked', false);
+  }
+
   public static function getStatusActionName($status) {
     return self::getStatusAttribute($status, 'name.action');
   }
@@ -277,6 +281,7 @@ final class ManiphestTaskStatus extends ManiphestConstants {
           'keywords' => 'optional list<string>',
           'disabled' => 'optional bool',
           'claim' => 'optional bool',
+          'locked' => 'optional bool',
         ));
     }
 
diff --git a/src/applications/maniphest/controller/ManiphestTaskDetailController.php b/src/applications/maniphest/controller/ManiphestTaskDetailController.php
index 60d3a81b1b..514090dda8 100644
--- a/src/applications/maniphest/controller/ManiphestTaskDetailController.php
+++ b/src/applications/maniphest/controller/ManiphestTaskDetailController.php
@@ -257,6 +257,12 @@ final class ManiphestTaskDetailController extends ManiphestController {
       $task,
       PhabricatorPolicyCapability::CAN_EDIT);
 
+    $can_interact = PhabricatorPolicyFilter::canInteract($viewer, $task);
+
+    // We expect a policy dialog if you can't edit the task, and expect a
+    // lock override dialog if you can't interact with it.
+    $workflow_edit = (!$can_edit || !$can_interact);
+
     $curtain = $this->newCurtainView($task);
 
     $curtain->addAction(
@@ -265,7 +271,7 @@ final class ManiphestTaskDetailController extends ManiphestController {
         ->setIcon('fa-pencil')
         ->setHref($this->getApplicationURI("/task/edit/{$id}/"))
         ->setDisabled(!$can_edit)
-        ->setWorkflow(!$can_edit));
+        ->setWorkflow($workflow_edit));
 
     $edit_config = $edit_engine->loadDefaultEditConfiguration($task);
     $can_create = (bool)$edit_config;
diff --git a/src/applications/maniphest/editor/ManiphestTaskEditEngineLock.php b/src/applications/maniphest/editor/ManiphestTaskEditEngineLock.php
new file mode 100644
index 0000000000..5f51ef242f
--- /dev/null
+++ b/src/applications/maniphest/editor/ManiphestTaskEditEngineLock.php
@@ -0,0 +1,28 @@
+<?php
+
+final class ManiphestTaskEditEngineLock
+  extends PhabricatorEditEngineLock {
+
+  public function willPromptUserForLockOverrideWithDialog(
+    AphrontDialogView $dialog) {
+
+    return $dialog
+      ->setTitle(pht('Edit Locked Task'))
+      ->appendParagraph(pht('This task is locked. Edit it anyway?'))
+      ->addSubmitButton(pht('Override Task Lock'));
+  }
+
+  public function willBlockUserInteractionWithDialog(
+    AphrontDialogView $dialog) {
+
+    return $dialog
+      ->setTitle(pht('Task Locked'))
+      ->appendParagraph(
+        pht('You can not interact with this task because it is locked.'));
+  }
+
+  public function getLockedObjectDisplayText() {
+    return pht('This task has been locked.');
+  }
+
+}
diff --git a/src/applications/maniphest/storage/ManiphestTask.php b/src/applications/maniphest/storage/ManiphestTask.php
index be540b9056..36d0a21b07 100644
--- a/src/applications/maniphest/storage/ManiphestTask.php
+++ b/src/applications/maniphest/storage/ManiphestTask.php
@@ -17,7 +17,8 @@ final class ManiphestTask extends ManiphestDAO
     PhabricatorConduitResultInterface,
     PhabricatorFulltextInterface,
     DoorkeeperBridgedObjectInterface,
-    PhabricatorEditEngineSubtypeInterface {
+    PhabricatorEditEngineSubtypeInterface,
+    PhabricatorEditEngineLockableInterface {
 
   const MARKUP_FIELD_DESCRIPTION = 'markup:desc';
 
@@ -213,6 +214,10 @@ final class ManiphestTask extends ManiphestDAO
     return ManiphestTaskStatus::isClosedStatus($this->getStatus());
   }
 
+  public function isLocked() {
+    return ManiphestTaskStatus::isLockedStatus($this->getStatus());
+  }
+
   public function setProperty($key, $value) {
     $this->properties[$key] = $value;
     return $this;
@@ -343,6 +348,7 @@ final class ManiphestTask extends ManiphestDAO
   public function getCapabilities() {
     return array(
       PhabricatorPolicyCapability::CAN_VIEW,
+      PhabricatorPolicyCapability::CAN_INTERACT,
       PhabricatorPolicyCapability::CAN_EDIT,
     );
   }
@@ -351,6 +357,12 @@ final class ManiphestTask extends ManiphestDAO
     switch ($capability) {
       case PhabricatorPolicyCapability::CAN_VIEW:
         return $this->getViewPolicy();
+      case PhabricatorPolicyCapability::CAN_INTERACT:
+        if ($this->isLocked()) {
+          return PhabricatorPolicies::POLICY_NOONE;
+        } else {
+          return PhabricatorPolicies::POLICY_USER;
+        }
       case PhabricatorPolicyCapability::CAN_EDIT:
         return $this->getEditPolicy();
     }
@@ -562,4 +574,12 @@ final class ManiphestTask extends ManiphestDAO
     return PhabricatorEditEngineSubtype::newSubtypeMap($config);
   }
 
+
+/* -(  PhabricatorEditEngineLockableInterface  )----------------------------- */
+
+
+  public function newEditEngineLock() {
+    return new ManiphestTaskEditEngineLock();
+  }
+
 }
diff --git a/src/applications/policy/capability/PhabricatorPolicyCapability.php b/src/applications/policy/capability/PhabricatorPolicyCapability.php
index 36b8ea87c0..2bb1ce4238 100644
--- a/src/applications/policy/capability/PhabricatorPolicyCapability.php
+++ b/src/applications/policy/capability/PhabricatorPolicyCapability.php
@@ -5,6 +5,7 @@ abstract class PhabricatorPolicyCapability extends Phobject {
   const CAN_VIEW        = 'view';
   const CAN_EDIT        = 'edit';
   const CAN_JOIN        = 'join';
+  const CAN_INTERACT    = 'interact';
 
   /**
    * Get the unique key identifying this capability. This key must be globally
diff --git a/src/applications/policy/filter/PhabricatorPolicyFilter.php b/src/applications/policy/filter/PhabricatorPolicyFilter.php
index 44931085fc..f3e1bd2083 100644
--- a/src/applications/policy/filter/PhabricatorPolicyFilter.php
+++ b/src/applications/policy/filter/PhabricatorPolicyFilter.php
@@ -86,6 +86,36 @@ final class PhabricatorPolicyFilter extends Phobject {
     return (count($result) == 1);
   }
 
+  public static function canInteract(
+    PhabricatorUser $user,
+    PhabricatorPolicyInterface $object) {
+
+    $capabilities = $object->getCapabilities();
+    $capabilities = array_fuse($capabilities);
+
+    $can_interact = PhabricatorPolicyCapability::CAN_INTERACT;
+    $can_view = PhabricatorPolicyCapability::CAN_VIEW;
+
+    $require = array();
+
+    // If the object doesn't support a separate "Interact" capability, we
+    // only use the "View" capability: for most objects, you can interact
+    // with them if you can see them.
+    $require[] = $can_view;
+
+    if (isset($capabilities[$can_interact])) {
+      $require[] = $can_interact;
+    }
+
+    foreach ($require as $capability) {
+      if (!self::hasCapability($user, $object, $capability)) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
   public function setViewer(PhabricatorUser $user) {
     $this->viewer = $user;
     return $this;
diff --git a/src/applications/subscriptions/controller/PhabricatorSubscriptionsEditController.php b/src/applications/subscriptions/controller/PhabricatorSubscriptionsEditController.php
index add833c127..e005c120f0 100644
--- a/src/applications/subscriptions/controller/PhabricatorSubscriptionsEditController.php
+++ b/src/applications/subscriptions/controller/PhabricatorSubscriptionsEditController.php
@@ -47,6 +47,15 @@ final class PhabricatorSubscriptionsEditController
         $handle->getURI());
     }
 
+    if (!PhabricatorPolicyFilter::canInteract($viewer, $object)) {
+      $lock = PhabricatorEditEngineLock::newForObject($viewer, $object);
+
+      $dialog = $this->newDialog()
+        ->addCancelButton($handle->getURI());
+
+      return $lock->willBlockUserInteractionWithDialog($dialog);
+    }
+
     if ($object instanceof PhabricatorApplicationTransactionInterface) {
       if ($is_add) {
         $xaction_value = array(
diff --git a/src/applications/subscriptions/events/PhabricatorSubscriptionsUIEventListener.php b/src/applications/subscriptions/events/PhabricatorSubscriptionsUIEventListener.php
index acbb978238..09b26819c0 100644
--- a/src/applications/subscriptions/events/PhabricatorSubscriptionsUIEventListener.php
+++ b/src/applications/subscriptions/events/PhabricatorSubscriptionsUIEventListener.php
@@ -56,20 +56,24 @@ final class PhabricatorSubscriptionsUIEventListener
         $subscribed = isset($edges[$src_phid][$edge_type][$user_phid]);
       }
 
+      $can_interact = PhabricatorPolicyFilter::canInteract($user, $object);
+
       if ($subscribed) {
         $sub_action = id(new PhabricatorActionView())
           ->setWorkflow(true)
           ->setRenderAsForm(true)
           ->setHref('/subscriptions/delete/'.$object->getPHID().'/')
           ->setName(pht('Unsubscribe'))
-          ->setIcon('fa-minus-circle');
+          ->setIcon('fa-minus-circle')
+          ->setDisabled(!$can_interact);
       } else {
         $sub_action = id(new PhabricatorActionView())
           ->setWorkflow(true)
           ->setRenderAsForm(true)
           ->setHref('/subscriptions/add/'.$object->getPHID().'/')
           ->setName(pht('Subscribe'))
-          ->setIcon('fa-plus-circle');
+          ->setIcon('fa-plus-circle')
+          ->setDisabled(!$can_interact);
       }
 
       if (!$user->isLoggedIn()) {
diff --git a/src/applications/transactions/editengine/PhabricatorEditEngine.php b/src/applications/transactions/editengine/PhabricatorEditEngine.php
index 9d769c0e66..4ad6e39be8 100644
--- a/src/applications/transactions/editengine/PhabricatorEditEngine.php
+++ b/src/applications/transactions/editengine/PhabricatorEditEngine.php
@@ -985,9 +985,33 @@ abstract class PhabricatorEditEngine
     $fields = $this->buildEditFields($object);
     $template = $object->getApplicationTransactionTemplate();
 
+    if ($this->getIsCreate()) {
+      $cancel_uri = $this->getObjectCreateCancelURI($object);
+      $submit_button = $this->getObjectCreateButtonText($object);
+    } else {
+      $cancel_uri = $this->getEffectiveObjectEditCancelURI($object);
+      $submit_button = $this->getObjectEditButtonText($object);
+    }
+
     $config = $this->getEditEngineConfiguration()
       ->attachEngine($this);
 
+    $can_interact = PhabricatorPolicyFilter::canInteract($viewer, $object);
+    if (!$can_interact &&
+        !$request->getBool('editEngine') &&
+        !$request->getBool('overrideLock')) {
+
+      $lock = PhabricatorEditEngineLock::newForObject($viewer, $object);
+
+      $dialog = $this->getController()
+        ->newDialog()
+        ->addHiddenInput('overrideLock', true)
+        ->setDisableWorkflowOnSubmit(true)
+        ->addCancelButton($cancel_uri);
+
+      return $lock->willPromptUserForLockOverrideWithDialog($dialog);
+    }
+
     $validation_exception = null;
     if ($request->isFormPost() && $request->getBool('editEngine')) {
       $submit_fields = $fields;
@@ -1154,14 +1178,6 @@ abstract class PhabricatorEditEngine
     $form = $this->buildEditForm($object, $fields);
 
     if ($request->isAjax()) {
-      if ($this->getIsCreate()) {
-        $cancel_uri = $this->getObjectCreateCancelURI($object);
-        $submit_button = $this->getObjectCreateButtonText($object);
-      } else {
-        $cancel_uri = $this->getEffectiveObjectEditCancelURI($object);
-        $submit_button = $this->getObjectEditButtonText($object);
-      }
-
       return $this->getController()
         ->newDialog()
         ->setWidth(AphrontDialogView::WIDTH_FULL)
@@ -1554,8 +1570,16 @@ abstract class PhabricatorEditEngine
     }
 
     $viewer = $this->getViewer();
-    $object_phid = $object->getPHID();
 
+    $can_interact = PhabricatorPolicyFilter::canInteract($viewer, $object);
+    if (!$can_interact) {
+      $lock = PhabricatorEditEngineLock::newForObject($viewer, $object);
+
+      return id(new PhabricatorApplicationTransactionCommentView())
+        ->setEditEngineLock($lock);
+    }
+
+    $object_phid = $object->getPHID();
     $is_serious = PhabricatorEnv::getEnvConfig('phabricator.serious-business');
 
     if ($is_serious) {
@@ -1700,11 +1724,19 @@ abstract class PhabricatorEditEngine
   private function buildError($object, $title, $body) {
     $cancel_uri = $this->getObjectCreateCancelURI($object);
 
-    return $this->getController()
+    $dialog = $this->getController()
       ->newDialog()
-      ->setTitle($title)
-      ->appendParagraph($body)
       ->addCancelButton($cancel_uri);
+
+    if ($title !== null) {
+      $dialog->setTitle($title);
+    }
+
+    if ($body !== null) {
+      $dialog->appendParagraph($body);
+    }
+
+    return $dialog;
   }
 
 
@@ -1761,6 +1793,14 @@ abstract class PhabricatorEditEngine
         $config->getName()));
   }
 
+  private function buildLockedObjectResponse($object) {
+    $dialog = $this->buildError($object, null, null);
+    $viewer = $this->getViewer();
+
+    $lock = PhabricatorEditEngineLock::newForObject($viewer, $object);
+    return $lock->willBlockUserInteractionWithDialog($dialog);
+  }
+
   private function buildCommentResponse($object) {
     $viewer = $this->getViewer();
 
@@ -1775,6 +1815,11 @@ abstract class PhabricatorEditEngine
       return new Aphront400Response();
     }
 
+    $can_interact = PhabricatorPolicyFilter::canInteract($viewer, $object);
+    if (!$can_interact) {
+      return $this->buildLockedObjectResponse($object);
+    }
+
     $config = $this->loadDefaultEditConfiguration($object);
     if (!$config) {
       return new Aphront404Response();
diff --git a/src/applications/transactions/editengine/PhabricatorEditEngineDefaultLock.php b/src/applications/transactions/editengine/PhabricatorEditEngineDefaultLock.php
new file mode 100644
index 0000000000..dc1118344a
--- /dev/null
+++ b/src/applications/transactions/editengine/PhabricatorEditEngineDefaultLock.php
@@ -0,0 +1,4 @@
+<?php
+
+final class PhabricatorEditEngineDefaultLock
+  extends PhabricatorEditEngineLock {}
diff --git a/src/applications/transactions/editengine/PhabricatorEditEngineLock.php b/src/applications/transactions/editengine/PhabricatorEditEngineLock.php
new file mode 100644
index 0000000000..6de116bd6f
--- /dev/null
+++ b/src/applications/transactions/editengine/PhabricatorEditEngineLock.php
@@ -0,0 +1,66 @@
+<?php
+
+abstract class PhabricatorEditEngineLock
+  extends Phobject {
+
+  private $viewer;
+  private $object;
+
+  final public function setViewer(PhabricatorUser $viewer) {
+    $this->viewer = $viewer;
+    return $this;
+  }
+
+  final public function getViewer() {
+    return $this->viewer;
+  }
+
+  final public function setObject($object) {
+    $this->object = $object;
+    return $this;
+  }
+
+  final public function getObject() {
+    return $this->object;
+  }
+
+  public function willPromptUserForLockOverrideWithDialog(
+    AphrontDialogView $dialog) {
+
+    return $dialog
+      ->setTitle(pht('Edit Locked Object'))
+      ->appendParagraph(pht('This object is locked. Edit it anyway?'))
+      ->addSubmitButton(pht('Override Lock'));
+  }
+
+  public function willBlockUserInteractionWithDialog(
+    AphrontDialogView $dialog) {
+
+    return $dialog
+      ->setTitle(pht('Object Locked'))
+      ->appendParagraph(
+        pht('You can not interact with this object because it is locked.'));
+  }
+
+  public function getLockedObjectDisplayText() {
+    return pht('This object has been locked.');
+  }
+
+  public static function newForObject(
+    PhabricatorUser $viewer,
+    $object) {
+
+    if ($object instanceof PhabricatorEditEngineLockableInterface) {
+      $lock = $object->newEditEngineLock();
+    } else {
+      $lock = new PhabricatorEditEngineDefaultLock();
+    }
+
+    return $lock
+      ->setViewer($viewer)
+      ->setObject($object);
+  }
+
+
+
+}
diff --git a/src/applications/transactions/editengine/PhabricatorEditEngineLockableInterface.php b/src/applications/transactions/editengine/PhabricatorEditEngineLockableInterface.php
new file mode 100644
index 0000000000..8d7587728b
--- /dev/null
+++ b/src/applications/transactions/editengine/PhabricatorEditEngineLockableInterface.php
@@ -0,0 +1,7 @@
+<?php
+
+interface PhabricatorEditEngineLockableInterface {
+
+  public function newEditEngineLock();
+
+}
diff --git a/src/applications/transactions/view/PhabricatorApplicationTransactionCommentView.php b/src/applications/transactions/view/PhabricatorApplicationTransactionCommentView.php
index 996b12bc51..2d4c5e6f95 100644
--- a/src/applications/transactions/view/PhabricatorApplicationTransactionCommentView.php
+++ b/src/applications/transactions/view/PhabricatorApplicationTransactionCommentView.php
@@ -22,6 +22,7 @@ class PhabricatorApplicationTransactionCommentView extends AphrontView {
   private $noPermission;
   private $fullWidth;
   private $infoView;
+  private $editEngineLock;
 
   private $currentVersion;
   private $versionedDraft;
@@ -149,11 +150,20 @@ class PhabricatorApplicationTransactionCommentView extends AphrontView {
     return $this->noPermission;
   }
 
+  public function setEditEngineLock(PhabricatorEditEngineLock $lock) {
+    $this->editEngineLock = $lock;
+    return $this;
+  }
+
+  public function getEditEngineLock() {
+    return $this->editEngineLock;
+  }
+
   public function setTransactionTimeline(
     PhabricatorApplicationTransactionView $timeline) {
 
     $timeline->setQuoteTargetID($this->getCommentID());
-    if ($this->getNoPermission()) {
+    if ($this->getNoPermission() || $this->getEditEngineLock()) {
       $timeline->setShouldTerminate(true);
     }
 
@@ -166,6 +176,16 @@ class PhabricatorApplicationTransactionCommentView extends AphrontView {
       return null;
     }
 
+    $lock = $this->getEditEngineLock();
+    if ($lock) {
+      return id(new PHUIInfoView())
+        ->setSeverity(PHUIInfoView::SEVERITY_WARNING)
+        ->setErrors(
+          array(
+            $lock->getLockedObjectDisplayText(),
+          ));
+    }
+
     $user = $this->getUser();
     if (!$user->isLoggedIn()) {
       $uri = id(new PhutilURI('/login/'))