diff --git a/src/applications/differential/storage/DifferentialViewState.php b/src/applications/differential/storage/DifferentialViewState.php
index 101061f379..44c1f308d8 100644
--- a/src/applications/differential/storage/DifferentialViewState.php
+++ b/src/applications/differential/storage/DifferentialViewState.php
@@ -1,145 +1,150 @@
 <?php
 
 final class DifferentialViewState
   extends DifferentialDAO
   implements PhabricatorPolicyInterface {
 
   protected $viewerPHID;
   protected $objectPHID;
   protected $viewState = array();
 
   private $hasModifications;
 
   protected function getConfiguration() {
     return array(
       self::CONFIG_SERIALIZATION => array(
         'viewState' => self::SERIALIZATION_JSON,
       ),
       self::CONFIG_KEY_SCHEMA => array(
         'key_viewer' => array(
           'columns' => array('viewerPHID', 'objectPHID'),
           'unique' => true,
         ),
         'key_object' => array(
           'columns' => array('objectPHID'),
         ),
         'key_modified' => array(
           'columns' => array('dateModified'),
         ),
       ),
     ) + parent::getConfiguration();
   }
 
   public function setChangesetProperty(
     DifferentialChangeset $changeset,
     $key,
     $value) {
 
     if ($this->getChangesetProperty($changeset, $key) === $value) {
       return;
     }
 
     $properties = array(
       'value' => $value,
       'epoch' => PhabricatorTime::getNow(),
     );
 
     $diff_id = $changeset->getDiffID();
     if ($diff_id !== null) {
       $properties['diffID'] = (int)$diff_id;
     }
 
+    $changeset_id = $changeset->getID();
+    if ($changeset_id !== null) {
+      $properties['changesetID'] = (int)$changeset_id;
+    }
+
     $path_hash = $this->getChangesetPathHash($changeset);
     $changeset_phid = $this->getChangesetKey($changeset);
 
     $this->hasModifications = true;
 
     $this->viewState['changesets'][$path_hash][$key][$changeset_phid] =
       $properties;
   }
 
   public function getChangesetProperty(
     DifferentialChangeset $changeset,
     $key,
     $default = null) {
 
     $entries = $this->getChangesetPropertyEntries(
       $changeset,
       $key);
 
     $entries = isort($entries, 'epoch');
 
     $entry = last($entries);
     if (!is_array($entry)) {
       $entry = array();
     }
 
     return idx($entry, 'value', $default);
   }
 
   public function getChangesetPropertyEntries(
     DifferentialChangeset $changeset,
     $key) {
     $path_hash = $this->getChangesetPathHash($changeset);
 
     $entries = idxv($this->viewState, array('changesets', $path_hash, $key));
     if (!is_array($entries)) {
       $entries = array();
     }
 
     return $entries;
   }
 
   public function getHasModifications() {
     return $this->hasModifications;
   }
 
   private function getChangesetPathHash(DifferentialChangeset $changeset) {
     $path = $changeset->getFilename();
     return PhabricatorHash::digestForIndex($path);
   }
 
   private function getChangesetKey(DifferentialChangeset $changeset) {
     $key = $changeset->getID();
 
     if ($key === null) {
       return '*';
     }
 
     return (string)$key;
   }
 
   public static function copyViewStatesToObject($src_phid, $dst_phid) {
     $table = new self();
     $conn = $table->establishConnection('w');
 
     queryfx(
       $conn,
       'INSERT IGNORE INTO %R
           (viewerPHID, objectPHID, viewState, dateCreated, dateModified)
         SELECT viewerPHID, %s, viewState, dateCreated, dateModified
           FROM %R WHERE objectPHID = %s',
       $table,
       $dst_phid,
       $table,
       $src_phid);
   }
 
 /* -(  PhabricatorPolicyInterface  )----------------------------------------- */
 
 
   public function getCapabilities() {
     return array(
       PhabricatorPolicyCapability::CAN_VIEW,
     );
   }
 
   public function getPolicy($capability) {
     return PhabricatorPolicies::POLICY_NOONE;
   }
 
   public function hasAutomaticCapability($capability, PhabricatorUser $viewer) {
     return ($viewer->getPHID() === $this->getViewerPHID());
   }
 
 }
diff --git a/src/infrastructure/diff/viewstate/PhabricatorChangesetViewStateEngine.php b/src/infrastructure/diff/viewstate/PhabricatorChangesetViewStateEngine.php
index 2363f7f0ff..5979ca2a7b 100644
--- a/src/infrastructure/diff/viewstate/PhabricatorChangesetViewStateEngine.php
+++ b/src/infrastructure/diff/viewstate/PhabricatorChangesetViewStateEngine.php
@@ -1,235 +1,239 @@
 <?php
 
 final class PhabricatorChangesetViewStateEngine
   extends Phobject {
 
   private $viewer;
   private $objectPHID;
   private $changeset;
   private $storage;
 
   public function setViewer(PhabricatorUser $viewer) {
     $this->viewer = $viewer;
     return $this;
   }
 
   public function getViewer() {
     return $this->viewer;
   }
 
   public function setObjectPHID($object_phid) {
     $this->objectPHID = $object_phid;
     return $this;
   }
 
   public function getObjectPHID() {
     return $this->objectPHID;
   }
 
   public function setChangeset(DifferentialChangeset $changeset) {
     $this->changeset = $changeset;
     return $this;
   }
 
   public function getChangeset() {
     return $this->changeset;
   }
 
   public function newViewStateFromRequest(AphrontRequest $request) {
     $storage = $this->loadViewStateStorage();
 
     $this->setStorage($storage);
 
     $highlight = $request->getStr('highlight');
     if ($highlight !== null) {
       $this->setChangesetProperty('highlight', $highlight);
     }
 
     $encoding = $request->getStr('encoding');
     if ($encoding !== null) {
       $this->setChangesetProperty('encoding', $encoding);
     }
 
     $engine = $request->getStr('engine');
     if ($engine !== null) {
       $this->setChangesetProperty('engine', $engine);
     }
 
     $renderer = $request->getStr('renderer');
     if ($renderer !== null) {
       $this->setChangesetProperty('renderer', $renderer);
     }
 
     $hidden = $request->getStr('hidden');
     if ($hidden !== null) {
       $this->setChangesetProperty('hidden', (int)$hidden);
     }
 
     $this->saveViewStateStorage();
 
     $state = new PhabricatorChangesetViewState();
 
     $highlight_language = $this->getChangesetProperty('highlight');
     $state->setHighlightLanguage($highlight_language);
 
     $encoding = $this->getChangesetProperty('encoding');
     $state->setCharacterEncoding($encoding);
 
     $document_engine = $this->getChangesetProperty('engine');
     $state->setDocumentEngineKey($document_engine);
 
     $renderer = $this->getChangesetProperty('renderer');
     $state->setRendererKey($renderer);
 
     $this->updateHiddenState($state);
 
     // This is the client-selected default renderer based on viewport
     // dimensions.
 
     $device_key = $request->getStr('device');
     if ($device_key !== null) {
       $state->setDefaultDeviceRendererKey($device_key);
     }
 
     $discard_response = $request->getStr('discard');
     if ($discard_response !== null) {
       $state->setDiscardResponse(true);
     }
 
     return $state;
   }
 
   private function setStorage(DifferentialViewState $storage) {
     $this->storage = $storage;
     return $this;
   }
 
   private function getStorage() {
     return $this->storage;
   }
 
   private function setChangesetProperty(
     $key,
     $value) {
 
     $storage = $this->getStorage();
     $changeset = $this->getChangeset();
 
     $storage->setChangesetProperty($changeset, $key, $value);
   }
 
   private function getChangesetProperty(
     $key,
     $default = null) {
 
     $storage = $this->getStorage();
     $changeset = $this->getChangeset();
 
     return $storage->getChangesetProperty($changeset, $key, $default);
   }
 
   private function loadViewStateStorage() {
     $viewer = $this->getViewer();
 
     $object_phid = $this->getObjectPHID();
     $viewer_phid = $viewer->getPHID();
 
     $storage = null;
 
     if ($viewer_phid !== null) {
       $storage = id(new DifferentialViewStateQuery())
         ->setViewer($viewer)
         ->withViewerPHIDs(array($viewer_phid))
         ->withObjectPHIDs(array($object_phid))
         ->executeOne();
     }
 
     if ($storage === null) {
       $storage = id(new DifferentialViewState())
         ->setObjectPHID($object_phid);
 
       if ($viewer_phid !== null) {
         $storage->setViewerPHID($viewer_phid);
       } else {
         $storage->makeEphemeral();
       }
     }
 
     return $storage;
   }
 
   private function saveViewStateStorage() {
     if (PhabricatorEnv::isReadOnly()) {
       return;
     }
 
     $storage = $this->getStorage();
 
     $viewer_phid = $storage->getViewerPHID();
     if ($viewer_phid === null) {
       return;
     }
 
     if (!$storage->getHasModifications()) {
       return;
     }
 
     $unguarded = AphrontWriteGuard::beginScopedUnguardedWrites();
 
     try {
       $storage->save();
     } catch (AphrontDuplicateKeyQueryException $ex) {
       // We may race another process to save view state. For now, just discard
       // our state if we do.
     }
 
     unset($unguarded);
   }
 
   private function updateHiddenState(PhabricatorChangesetViewState $state) {
     $is_hidden = false;
     $was_modified = false;
 
     $storage = $this->getStorage();
     $changeset = $this->getChangeset();
 
     $entries = $storage->getChangesetPropertyEntries($changeset, 'hidden');
     $entries = isort($entries, 'epoch');
 
     if ($entries) {
-      $other_key = last_key($entries);
       $other_spec = last($entries);
 
       $this_version = (int)$changeset->getDiffID();
       $other_version = (int)idx($other_spec, 'diffID');
       $other_value = (bool)idx($other_spec, 'value', false);
+      $other_id = (int)idx($other_spec, 'changesetID');
 
       if ($other_value === false) {
         $is_hidden = false;
       } else if ($other_version >= $this_version) {
         $is_hidden = $other_value;
       } else {
         $viewer = $this->getViewer();
 
-        $other_changeset = id(new DifferentialChangesetQuery())
-          ->setViewer($viewer)
-          ->withIDs(array($other_key))
-          ->executeOne();
+        if ($other_id) {
+          $other_changeset = id(new DifferentialChangesetQuery())
+            ->setViewer($viewer)
+            ->withIDs(array($other_id))
+            ->executeOne();
+        } else {
+          $other_changeset = null;
+        }
 
         $is_modified = false;
         if ($other_changeset) {
           if (!$changeset->hasSameEffectAs($other_changeset)) {
             $is_modified = true;
           }
         }
 
         $is_hidden = false;
         $was_modified = true;
       }
     }
 
     $state->setHidden($is_hidden);
     $state->setModifiedSinceHide($was_modified);
   }
 
 }