diff --git a/src/applications/transactions/storage/PhabricatorApplicationTransaction.php b/src/applications/transactions/storage/PhabricatorApplicationTransaction.php
index e4fb7c52b9..fbb13222c9 100644
--- a/src/applications/transactions/storage/PhabricatorApplicationTransaction.php
+++ b/src/applications/transactions/storage/PhabricatorApplicationTransaction.php
@@ -1,570 +1,621 @@
 <?php
 
 abstract class PhabricatorApplicationTransaction
   extends PhabricatorLiskDAO
   implements PhabricatorPolicyInterface {
 
   const TARGET_TEXT = 'text';
   const TARGET_HTML = 'html';
 
   protected $phid;
   protected $objectPHID;
   protected $authorPHID;
   protected $viewPolicy;
   protected $editPolicy;
 
   protected $commentPHID;
   protected $commentVersion = 0;
   protected $transactionType;
   protected $oldValue;
   protected $newValue;
   protected $metadata = array();
 
   protected $contentSource;
 
   private $comment;
   private $commentNotLoaded;
 
   private $handles;
   private $renderingTarget = self::TARGET_HTML;
   private $transactionGroup = array();
   private $viewer = self::ATTACHABLE;
 
   abstract public function getApplicationTransactionType();
 
   private function getApplicationObjectTypeName() {
     $types = PhabricatorPHIDType::getAllTypes();
 
     $type = idx($types, $this->getApplicationTransactionType());
     if ($type) {
       return $type->getTypeName();
     }
 
     return pht('Object');
   }
 
   public function getApplicationTransactionCommentObject() {
     throw new Exception("Not implemented!");
   }
 
   public function getApplicationTransactionViewObject() {
     return new PhabricatorApplicationTransactionView();
   }
 
   public function getMetadataValue($key, $default = null) {
     return idx($this->metadata, $key, $default);
   }
 
   public function setMetadataValue($key, $value) {
     $this->metadata[$key] = $value;
     return $this;
   }
 
   public function generatePHID() {
     $type = PhabricatorApplicationTransactionPHIDTypeTransaction::TYPECONST;
     $subtype = $this->getApplicationTransactionType();
 
     return PhabricatorPHID::generateNewPHID($type, $subtype);
   }
 
   public function getConfiguration() {
     return array(
       self::CONFIG_AUX_PHID => true,
       self::CONFIG_SERIALIZATION => array(
         'oldValue' => self::SERIALIZATION_JSON,
         'newValue' => self::SERIALIZATION_JSON,
         'metadata' => self::SERIALIZATION_JSON,
       ),
     ) + parent::getConfiguration();
   }
 
   public function setContentSource(PhabricatorContentSource $content_source) {
     $this->contentSource = $content_source->serialize();
     return $this;
   }
 
   public function getContentSource() {
     return PhabricatorContentSource::newFromSerialized($this->contentSource);
   }
 
   public function hasComment() {
     return $this->getComment() && strlen($this->getComment()->getContent());
   }
 
   public function getComment() {
     if ($this->commentNotLoaded) {
       throw new Exception("Comment for this transaction was not loaded.");
     }
     return $this->comment;
   }
 
   public function attachComment(
     PhabricatorApplicationTransactionComment $comment) {
     $this->comment = $comment;
     $this->commentNotLoaded = false;
     return $this;
   }
 
   public function setCommentNotLoaded($not_loaded) {
     $this->commentNotLoaded = $not_loaded;
     return $this;
   }
 
 /* -(  Rendering  )---------------------------------------------------------- */
 
   public function setRenderingTarget($rendering_target) {
     $this->renderingTarget = $rendering_target;
     return $this;
   }
 
   public function getRenderingTarget() {
     return $this->renderingTarget;
   }
 
   public function attachViewer(PhabricatorUser $viewer) {
     $this->viewer = $viewer;
     return $this;
   }
 
   public function getViewer() {
     return $this->assertAttached($this->viewer);
   }
 
   public function getRequiredHandlePHIDs() {
     $phids = array();
 
     $old = $this->getOldValue();
     $new = $this->getNewValue();
 
     $phids[] = array($this->getAuthorPHID());
     switch ($this->getTransactionType()) {
       case PhabricatorTransactions::TYPE_SUBSCRIBERS:
         $phids[] = $old;
         $phids[] = $new;
         break;
       case PhabricatorTransactions::TYPE_EDGE:
         $phids[] = ipull($old, 'dst');
         $phids[] = ipull($new, 'dst');
         break;
       case PhabricatorTransactions::TYPE_EDIT_POLICY:
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
       case PhabricatorTransactions::TYPE_JOIN_POLICY:
         if (!PhabricatorPolicyQuery::isGlobalPolicy($old)) {
           $phids[] = array($old);
         }
         if (!PhabricatorPolicyQuery::isGlobalPolicy($new)) {
           $phids[] = array($new);
         }
         break;
     }
 
     return array_mergev($phids);
   }
 
   public function setHandles(array $handles) {
     $this->handles = $handles;
     return $this;
   }
 
   public function getHandle($phid) {
     if (empty($this->handles[$phid])) {
       throw new Exception(
         "Transaction requires a handle ('{$phid}') it did not load.");
     }
     return $this->handles[$phid];
   }
 
   public function getHandleIfExists($phid) {
     return idx($this->handles, $phid);
   }
 
   public function getHandles() {
     if ($this->handles === null) {
       throw new Exception(
         'Transaction requires handles and it did not load them.'
       );
     }
     return $this->handles;
   }
 
   public function renderHandleLink($phid) {
     if ($this->renderingTarget == self::TARGET_HTML) {
       return $this->getHandle($phid)->renderLink();
     } else {
       return $this->getHandle($phid)->getLinkName();
     }
   }
 
   public function renderHandleList(array $phids) {
     $links = array();
     foreach ($phids as $phid) {
       $links[] = $this->renderHandleLink($phid);
     }
     if ($this->renderingTarget == self::TARGET_HTML) {
       return phutil_implode_html(', ', $links);
     } else {
       return implode(', ', $links);
     }
   }
 
   public function renderPolicyName($phid) {
     $policy = PhabricatorPolicy::newFromPolicyAndHandle(
       $phid,
       $this->getHandleIfExists($phid));
     if ($this->renderingTarget == self::TARGET_HTML) {
       $output = $policy->renderDescription();
     } else {
       $output = hsprintf('%s', $policy->getFullName());
     }
     return $output;
   }
 
   public function getIcon() {
     switch ($this->getTransactionType()) {
       case PhabricatorTransactions::TYPE_COMMENT:
         return 'comment';
       case PhabricatorTransactions::TYPE_SUBSCRIBERS:
         return 'message';
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
       case PhabricatorTransactions::TYPE_EDIT_POLICY:
       case PhabricatorTransactions::TYPE_JOIN_POLICY:
         return 'lock';
       case PhabricatorTransactions::TYPE_EDGE:
         return 'link';
     }
 
-    return null;
+    return 'edit';
   }
 
   public function getColor() {
     return null;
   }
 
   public function shouldHide() {
     switch ($this->getTransactionType()) {
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
       case PhabricatorTransactions::TYPE_EDIT_POLICY:
       case PhabricatorTransactions::TYPE_JOIN_POLICY:
         if ($this->getOldValue() === null) {
           return true;
         } else {
           return false;
         }
         break;
     }
 
     return false;
   }
 
   public function shouldHideForMail() {
     return $this->shouldHide();
   }
 
   public function getNoEffectDescription() {
 
     switch ($this->getTransactionType()) {
       case PhabricatorTransactions::TYPE_COMMENT:
         return pht('You can not post an empty comment.');
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
         return pht(
           'This %s already has that view policy.',
           $this->getApplicationObjectTypeName());
       case PhabricatorTransactions::TYPE_EDIT_POLICY:
         return pht(
           'This %s already has that edit policy.',
           $this->getApplicationObjectTypeName());
       case PhabricatorTransactions::TYPE_JOIN_POLICY:
         return pht(
           'This %s already has that join policy.',
           $this->getApplicationObjectTypeName());
       case PhabricatorTransactions::TYPE_SUBSCRIBERS:
         return pht(
           'All users are already subscribed to this %s.',
           $this->getApplicationObjectTypeName());
       case PhabricatorTransactions::TYPE_EDGE:
         return pht('Edges already exist; transaction has no effect.');
     }
 
     return pht('Transaction has no effect.');
   }
 
   public function getTitle() {
     $author_phid = $this->getAuthorPHID();
 
     $old = $this->getOldValue();
     $new = $this->getNewValue();
 
     switch ($this->getTransactionType()) {
       case PhabricatorTransactions::TYPE_COMMENT:
         return pht(
           '%s added a comment.',
           $this->renderHandleLink($author_phid));
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
         return pht(
           '%s changed the visibility of this %s from "%s" to "%s".',
           $this->renderHandleLink($author_phid),
           $this->getApplicationObjectTypeName(),
           $this->renderPolicyName($old),
           $this->renderPolicyName($new));
       case PhabricatorTransactions::TYPE_EDIT_POLICY:
         return pht(
           '%s changed the edit policy of this %s from "%s" to "%s".',
           $this->renderHandleLink($author_phid),
           $this->getApplicationObjectTypeName(),
           $this->renderPolicyName($old),
           $this->renderPolicyName($new));
       case PhabricatorTransactions::TYPE_JOIN_POLICY:
         return pht(
           '%s changed the join policy of this %s from "%s" to "%s".',
           $this->renderHandleLink($author_phid),
           $this->getApplicationObjectTypeName(),
           $this->renderPolicyName($old),
           $this->renderPolicyName($new));
       case PhabricatorTransactions::TYPE_SUBSCRIBERS:
         $add = array_diff($new, $old);
         $rem = array_diff($old, $new);
 
         if ($add && $rem) {
           return pht(
             '%s edited subscriber(s), added %d: %s; removed %d: %s.',
             $this->renderHandleLink($author_phid),
             count($add),
             $this->renderHandleList($add),
             count($rem),
             $this->renderHandleList($rem));
         } else if ($add) {
           return pht(
             '%s added %d subscriber(s): %s.',
             $this->renderHandleLink($author_phid),
             count($add),
             $this->renderHandleList($add));
         } else if ($rem) {
           return pht(
             '%s removed %d subscriber(s): %s.',
             $this->renderHandleLink($author_phid),
             count($rem),
             $this->renderHandleList($rem));
         } else {
           // This is used when rendering previews, before the user actually
           // selects any CCs.
           return pht(
             '%s updated subscribers...',
             $this->renderHandleLink($author_phid));
         }
         break;
       case PhabricatorTransactions::TYPE_EDGE:
         $new = ipull($new, 'dst');
         $old = ipull($old, 'dst');
         $add = array_diff($new, $old);
         $rem = array_diff($old, $new);
         $type = $this->getMetadata('edge:type');
         $type = head($type);
 
         if ($add && $rem) {
           $string = PhabricatorEdgeConfig::getEditStringForEdgeType($type);
           return pht(
             $string,
             $this->renderHandleLink($author_phid),
             count($add),
             $this->renderHandleList($add),
             count($rem),
             $this->renderHandleList($rem));
         } else if ($add) {
           $string = PhabricatorEdgeConfig::getAddStringForEdgeType($type);
           return pht(
             $string,
             $this->renderHandleLink($author_phid),
             count($add),
             $this->renderHandleList($add));
         } else {
           $string = PhabricatorEdgeConfig::getRemoveStringForEdgeType($type);
           return pht(
             $string,
             $this->renderHandleLink($author_phid),
             count($rem),
             $this->renderHandleList($rem));
         }
 
       case PhabricatorTransactions::TYPE_CUSTOMFIELD:
         $key = $this->getMetadataValue('customfield:key');
         $field = PhabricatorCustomField::getObjectField(
           // TODO: This is a giant hack, but we currently don't have a way to
           // get the contextual object and this pathway is only hit by
           // Maniphest. We should provide a way to get the actual object here.
           new ManiphestTask(),
           PhabricatorCustomField::ROLE_APPLICATIONTRANSACTIONS,
           $key);
         if ($field) {
           $field->setViewer($this->getViewer());
           return $field->getApplicationTransactionTitle($this);
         } else {
           return pht(
             '%s edited a custom field.',
             $this->renderHandleLink($author_phid));
         }
 
       default:
         return pht(
           '%s edited this %s.',
           $this->renderHandleLink($author_phid),
           $this->getApplicationObjectTypeName());
     }
   }
 
   public function getTitleForFeed(PhabricatorFeedStory $story) {
     $author_phid = $this->getAuthorPHID();
     $object_phid = $this->getObjectPHID();
 
     $old = $this->getOldValue();
     $new = $this->getNewValue();
 
     switch ($this->getTransactionType()) {
       case PhabricatorTransactions::TYPE_COMMENT:
         return pht(
           '%s added a comment to %s.',
           $this->renderHandleLink($author_phid),
           $this->renderHandleLink($object_phid));
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
         return pht(
           '%s changed the visibility for %s.',
           $this->renderHandleLink($author_phid),
           $this->renderHandleLink($object_phid));
       case PhabricatorTransactions::TYPE_EDIT_POLICY:
         return pht(
           '%s changed the edit policy for %s.',
           $this->renderHandleLink($author_phid),
           $this->renderHandleLink($object_phid));
       case PhabricatorTransactions::TYPE_JOIN_POLICY:
         return pht(
           '%s changed the join policy for %s.',
           $this->renderHandleLink($author_phid),
           $this->renderHandleLink($object_phid));
       case PhabricatorTransactions::TYPE_SUBSCRIBERS:
         return pht(
           '%s updated subscribers of %s.',
           $this->renderHandleLink($author_phid),
           $this->renderHandleLink($object_phid));
       case PhabricatorTransactions::TYPE_EDGE:
         $type = $this->getMetadata('edge:type');
         $type = head($type);
         $string = PhabricatorEdgeConfig::getFeedStringForEdgeType($type);
         return pht(
           $string,
           $this->renderHandleLink($author_phid),
           $this->renderHandleLink($object_phid));
       case PhabricatorTransactions::TYPE_CUSTOMFIELD:
         $key = $this->getMetadataValue('customfield:key');
         $field = PhabricatorCustomField::getObjectField(
           // TODO: This is a giant hack, but we currently don't have a way to
           // get the contextual object and this pathway is only hit by
           // Maniphest. We should provide a way to get the actual object here.
           new ManiphestTask(),
           PhabricatorCustomField::ROLE_APPLICATIONTRANSACTIONS,
           $key);
         if ($field) {
           $field->setViewer($this->getViewer());
           return $field->getApplicationTransactionTitleForFeed($this, $story);
         } else {
           return pht(
             '%s edited a custom field on %s.',
             $this->renderHandleLink($author_phid),
             $this->renderHandleLink($object_phid));
         }
 
     }
 
     return $this->getTitle();
   }
 
   public function getBodyForFeed(PhabricatorFeedStory $story) {
     $old = $this->getOldValue();
     $new = $this->getNewValue();
 
     $body = null;
 
     switch ($this->getTransactionType()) {
       case PhabricatorTransactions::TYPE_COMMENT:
         $text = $this->getComment()->getContent();
         $body = phutil_escape_html_newlines(
           phutil_utf8_shorten($text, 128));
         break;
     }
     return $body;
   }
 
   public function getActionStrength() {
     switch ($this->getTransactionType()) {
       case PhabricatorTransactions::TYPE_COMMENT:
         return 0.5;
     }
     return 1.0;
   }
 
   public function getActionName() {
     switch ($this->getTransactionType()) {
       case PhabricatorTransactions::TYPE_COMMENT:
         return pht('Commented On');
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
       case PhabricatorTransactions::TYPE_EDIT_POLICY:
       case PhabricatorTransactions::TYPE_JOIN_POLICY:
         return pht('Changed Policy');
       case PhabricatorTransactions::TYPE_SUBSCRIBERS:
         return pht('Changed Subscribers');
       default:
         return pht('Updated');
     }
   }
 
   public function getMailTags() {
     return array();
   }
 
   public function hasChangeDetails() {
     return false;
   }
 
   public function renderChangeDetails(PhabricatorUser $viewer) {
     return null;
   }
 
   public function attachTransactionGroup(array $group) {
     assert_instances_of($group, 'PhabricatorApplicationTransaction');
     $this->transactionGroup = $group;
     return $this;
   }
 
   public function getTransactionGroup() {
     return $this->transactionGroup;
   }
 
+  /**
+   * Should this transaction be visually grouped with an existing transaction
+   * group?
+   *
+   * @param list<PhabricatorApplicationTransaction> List of transactions.
+   * @return bool True to display in a group with the other transactions.
+   */
+  public function shouldDisplayGroupWith(array $group) {
+    $type_comment = PhabricatorTransactions::TYPE_COMMENT;
+
+    $this_source = null;
+    if ($this->getContentSource()) {
+      $this_source = $this->getContentSource()->getSource();
+    }
+
+    foreach ($group as $xaction) {
+      // Don't group transactions by different authors.
+      if ($xaction->getAuthorPHID() != $this->getAuthorPHID()) {
+        return false;
+      }
+
+      // Don't group transactions for different objects.
+      if ($xaction->getObjectPHID() != $this->getObjectPHID()) {
+        return false;
+      }
+
+      // Don't group anything into a group which already has a comment.
+      if ($xaction->getTransactionType() == $type_comment) {
+        return false;
+      }
+
+      // Don't group transactions from different content sources.
+      $other_source = null;
+      if ($xaction->getContentSource()) {
+        $other_source = $xaction->getContentSource()->getSource();
+      }
+
+      if ($other_source != $this_source) {
+        return false;
+      }
+
+      // Don't group transactions which happened more than 2 minutes apart.
+      $apart = abs($xaction->getDateCreated() - $this->getDateCreated());
+      if ($apart > (60 * 2)) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
 
 /* -(  PhabricatorPolicyInterface Implementation  )-------------------------- */
 
 
   public function getCapabilities() {
     return array(
       PhabricatorPolicyCapability::CAN_VIEW,
       PhabricatorPolicyCapability::CAN_EDIT,
     );
   }
 
   public function getPolicy($capability) {
     switch ($capability) {
       case PhabricatorPolicyCapability::CAN_VIEW:
         return $this->getViewPolicy();
       case PhabricatorPolicyCapability::CAN_EDIT:
         return $this->getEditPolicy();
     }
   }
 
   public function hasAutomaticCapability($capability, PhabricatorUser $viewer) {
     return ($viewer->getPHID() == $this->getAuthorPHID());
   }
 
   public function describeAutomaticCapability($capability) {
     // TODO: (T603) Exact policies are unclear here.
     return null;
   }
 
 
 }
diff --git a/src/applications/transactions/view/PhabricatorApplicationTransactionView.php b/src/applications/transactions/view/PhabricatorApplicationTransactionView.php
index e64b5b86ff..aa1d856c12 100644
--- a/src/applications/transactions/view/PhabricatorApplicationTransactionView.php
+++ b/src/applications/transactions/view/PhabricatorApplicationTransactionView.php
@@ -1,299 +1,377 @@
 <?php
 
 /**
  * @concrete-extensible
  */
 class PhabricatorApplicationTransactionView extends AphrontView {
 
   private $transactions;
   private $engine;
   private $anchorOffset = 1;
   private $showEditActions = true;
   private $isPreview;
   private $objectPHID;
   private $isDetailView;
 
   public function setIsDetailView($is_detail_view) {
     $this->isDetailView = $is_detail_view;
     return $this;
   }
 
   public function setObjectPHID($object_phid) {
     $this->objectPHID = $object_phid;
     return $this;
   }
 
   public function getObjectPHID() {
     return $this->objectPHID;
   }
 
   public function setIsPreview($is_preview) {
     $this->isPreview = $is_preview;
     return $this;
   }
 
   public function setShowEditActions($show_edit_actions) {
     $this->showEditActions = $show_edit_actions;
     return $this;
   }
 
   public function getShowEditActions() {
     return $this->showEditActions;
   }
 
   public function setAnchorOffset($anchor_offset) {
     $this->anchorOffset = $anchor_offset;
     return $this;
   }
 
   public function setMarkupEngine(PhabricatorMarkupEngine $engine) {
     $this->engine = $engine;
     return $this;
   }
 
   public function setTransactions(array $transactions) {
     assert_instances_of($transactions, 'PhabricatorApplicationTransaction');
     $this->transactions = $transactions;
     return $this;
   }
 
   public function buildEvents() {
     $user = $this->getUser();
 
     $anchor = $this->anchorOffset;
-    $events = array();
 
     $xactions = $this->transactions;
-    foreach ($xactions as $key => $xaction) {
-      if ($xaction->shouldHide()) {
-        unset($xactions[$key]);
-      }
-    }
-
-    $last = null;
-    $last_key = null;
-    $groups = array();
-    foreach ($xactions as $key => $xaction) {
-      if ($last && $this->shouldGroupTransactions($last, $xaction)) {
-        $groups[$last_key][] = $xaction;
-        unset($xactions[$key]);
-      } else {
-        $last = $xaction;
-        $last_key = $key;
-      }
-    }
-
-    foreach ($xactions as $key => $xaction) {
-      $xaction->attachTransactionGroup(idx($groups, $key, array()));
-
-      $event = id(new PhabricatorTimelineEventView())
-        ->setUser($user)
-        ->setTransactionPHID($xaction->getPHID())
-        ->setUserHandle($xaction->getHandle($xaction->getAuthorPHID()))
-        ->setIcon($xaction->getIcon())
-        ->setColor($xaction->getColor());
-
-      $title = $xaction->getTitle();
-      if ($xaction->hasChangeDetails()) {
-        if ($this->isPreview || $this->isDetailView) {
-          $details = $this->buildChangeDetails($xaction);
-        } else {
-          $details = $this->buildChangeDetailsLink($xaction);
-        }
-        $title = array(
-          $title,
-          ' ',
-          $details,
-        );
-      }
-      $event->setTitle($title);
 
-      if ($this->isPreview) {
-        $event->setIsPreview(true);
-      } else {
-        $event
-          ->setDateCreated($xaction->getDateCreated())
-          ->setContentSource($xaction->getContentSource())
-          ->setAnchor($anchor);
+    $xactions = $this->filterHiddenTransactions($xactions);
+    $xactions = $this->groupRelatedTransactions($xactions);
+    $groups = $this->groupDisplayTransactions($xactions);
 
+    $events = array();
+    foreach ($groups as $group) {
+      $group_event = null;
+      foreach ($group as $xaction) {
+        $event = $this->renderEvent($xaction, $group, $anchor);
         $anchor++;
-      }
-
-      $has_deleted_comment = $xaction->getComment() &&
-        $xaction->getComment()->getIsDeleted();
-
-      if ($this->getShowEditActions() && !$this->isPreview) {
-        if ($xaction->getCommentVersion() > 1) {
-          $event->setIsEdited(true);
-        }
-
-        $can_edit = PhabricatorPolicyCapability::CAN_EDIT;
-
-        if ($xaction->hasComment() || $has_deleted_comment) {
-          $has_edit_capability = PhabricatorPolicyFilter::hasCapability(
-            $user,
-            $xaction,
-            $can_edit);
-          if ($has_edit_capability) {
-            $event->setIsEditable(true);
-          }
+        if (!$group_event) {
+          $group_event = $event;
+        } else {
+          $group_event->addEventToGroup($event);
         }
       }
-
-      $content = $this->renderTransactionContent($xaction);
-      if ($content) {
-        $event->appendChild($content);
-      }
-
-      $events[] = $event;
+      $events[] = $group_event;
     }
 
     return $events;
   }
 
   public function render() {
     if (!$this->getObjectPHID()) {
       throw new Exception("Call setObjectPHID() before render()!");
     }
 
     $view = new PhabricatorTimelineView();
     $events = $this->buildEvents();
     foreach ($events as $event) {
       $view->addEvent($event);
     }
 
     if ($this->getShowEditActions()) {
       $list_id = celerity_generate_unique_node_id();
 
       $view->setID($list_id);
 
       Javelin::initBehavior(
         'phabricator-transaction-list',
         array(
           'listID'      => $list_id,
           'objectPHID'  => $this->getObjectPHID(),
           'nextAnchor'  => $this->anchorOffset + count($events),
         ));
     }
 
     return $view->render();
   }
 
   protected function getOrBuildEngine() {
     if ($this->engine) {
       return $this->engine;
     }
 
     $field = PhabricatorApplicationTransactionComment::MARKUP_FIELD_COMMENT;
 
     $engine = id(new PhabricatorMarkupEngine())
       ->setViewer($this->getUser());
     foreach ($this->transactions as $xaction) {
       if (!$xaction->hasComment()) {
         continue;
       }
       $engine->addObject($xaction->getComment(), $field);
     }
     $engine->process();
 
     return $engine;
   }
 
   private function buildChangeDetails(
     PhabricatorApplicationTransaction $xaction) {
 
     Javelin::initBehavior('phabricator-reveal-content');
 
     $show_id = celerity_generate_unique_node_id();
     $hide_id = celerity_generate_unique_node_id();
     $content_id = celerity_generate_unique_node_id();
 
     $show_more = javelin_tag(
       'a',
       array(
         'href' => '#',
         'sigil' => 'reveal-content',
         'mustcapture' => true,
         'id' => $show_id,
         'style' => 'display: none',
         'meta' => array(
           'hideIDs' => array($show_id),
           'showIDs' => array($hide_id, $content_id),
         ),
       ),
       pht('(Show Details)'));
 
     $hide_more = javelin_tag(
       'a',
       array(
         'href' => '#',
         'sigil' => 'reveal-content',
         'mustcapture' => true,
         'id' => $hide_id,
         'meta' => array(
           'hideIDs' => array($hide_id, $content_id),
           'showIDs' => array($show_id),
         ),
       ),
       pht('(Hide Details)'));
 
     $content = phutil_tag(
       'div',
       array(
         'id'    => $content_id,
         'class' => 'phabricator-timeline-change-details',
       ),
       $xaction->renderChangeDetails($this->getUser()));
 
     return array(
       $show_more,
       $hide_more,
       $content,
     );
   }
 
   private function buildChangeDetailsLink(
     PhabricatorApplicationTransaction $xaction) {
 
     return javelin_tag(
       'a',
       array(
         'href' => '/transactions/detail/'.$xaction->getPHID().'/',
         'sigil' => 'transaction-detail',
         'mustcapture' => true,
         'meta' => array(
           'anchor' => $this->anchorOffset,
         ),
       ),
       pht('(Show Details)'));
   }
 
   protected function shouldGroupTransactions(
     PhabricatorApplicationTransaction $u,
     PhabricatorApplicationTransaction $v) {
     return false;
   }
 
   protected function renderTransactionContent(
     PhabricatorApplicationTransaction $xaction) {
 
     $field = PhabricatorApplicationTransactionComment::MARKUP_FIELD_COMMENT;
     $engine = $this->getOrBuildEngine();
     $comment = $xaction->getComment();
 
     if ($xaction->hasComment()) {
       if ($comment->getIsDeleted()) {
         return phutil_tag(
           'em',
           array(),
           pht('This comment has been deleted.'));
       } else {
         return $engine->getOutput($comment, $field);
       }
     }
 
     return null;
   }
 
+  private function filterHiddenTransactions(array $xactions) {
+    foreach ($xactions as $key => $xaction) {
+      if ($xaction->shouldHide()) {
+        unset($xactions[$key]);
+      }
+    }
+    return $xactions;
+  }
+
+  private function groupRelatedTransactions(array $xactions) {
+    $last = null;
+    $last_key = null;
+    $groups = array();
+    foreach ($xactions as $key => $xaction) {
+      if ($last && $this->shouldGroupTransactions($last, $xaction)) {
+        $groups[$last_key][] = $xaction;
+        unset($xactions[$key]);
+      } else {
+        $last = $xaction;
+        $last_key = $key;
+      }
+    }
+
+    foreach ($xactions as $key => $xaction) {
+      $xaction->attachTransactionGroup(idx($groups, $key, array()));
+    }
+
+    return $xactions;
+  }
+
+  private function groupDisplayTransactions(array $xactions) {
+    $groups = array();
+    $group = array();
+    foreach ($xactions as $xaction) {
+      if ($xaction->shouldDisplayGroupWith($group)) {
+        $group[] = $xaction;
+      } else {
+        if ($group) {
+          $groups[] = $group;
+        }
+        $group = array($xaction);
+      }
+    }
+
+    if ($group) {
+      $groups[] = $group;
+    }
+
+    foreach ($groups as $key => $group) {
+      $group = msort($group, 'getActionStrength');
+      $group = array_reverse($group);
+      $groups[$key] = $group;
+    }
+
+    return $groups;
+  }
+
+  private function renderEvent(
+    PhabricatorApplicationTransaction $xaction,
+    array $group,
+    $anchor) {
+    $viewer = $this->getUser();
+
+    $event = id(new PhabricatorTimelineEventView())
+      ->setUser($viewer)
+      ->setTransactionPHID($xaction->getPHID())
+      ->setUserHandle($xaction->getHandle($xaction->getAuthorPHID()))
+      ->setIcon($xaction->getIcon())
+      ->setColor($xaction->getColor());
+
+    if (!$this->shouldSuppressTitle($xaction, $group)) {
+      $title = $xaction->getTitle();
+      if ($xaction->hasChangeDetails()) {
+        if ($this->isPreview || $this->isDetailView) {
+          $details = $this->buildChangeDetails($xaction);
+        } else {
+          $details = $this->buildChangeDetailsLink($xaction);
+        }
+        $title = array(
+          $title,
+          ' ',
+          $details,
+        );
+      }
+      $event->setTitle($title);
+    }
+
+    if ($this->isPreview) {
+      $event->setIsPreview(true);
+    } else {
+      $event
+        ->setDateCreated($xaction->getDateCreated())
+        ->setContentSource($xaction->getContentSource())
+        ->setAnchor($anchor);
+    }
+
+    $has_deleted_comment = $xaction->getComment() &&
+      $xaction->getComment()->getIsDeleted();
+
+    if ($this->getShowEditActions() && !$this->isPreview) {
+      if ($xaction->getCommentVersion() > 1) {
+        $event->setIsEdited(true);
+      }
+
+      $can_edit = PhabricatorPolicyCapability::CAN_EDIT;
+
+      if ($xaction->hasComment() || $has_deleted_comment) {
+        $has_edit_capability = PhabricatorPolicyFilter::hasCapability(
+          $viewer,
+          $xaction,
+          $can_edit);
+        if ($has_edit_capability) {
+          $event->setIsEditable(true);
+        }
+      }
+    }
+
+    $content = $this->renderTransactionContent($xaction);
+    if ($content) {
+      $event->appendChild($content);
+    }
+
+    return $event;
+  }
+
+  private function shouldSuppressTitle(
+    PhabricatorApplicationTransaction $xaction,
+    array $group) {
+
+    // This is a little hard-coded, but we don't have any other reasonable
+    // cases for now. Suppress "commented on" if there are other actions in
+    // the display group.
+
+    if (count($group) > 1) {
+      $type_comment = PhabricatorTransactions::TYPE_COMMENT;
+      if ($xaction->getTransactionType() == $type_comment) {
+        return true;
+      }
+    }
+
+    return false;
+  }
+
 }
 
diff --git a/src/view/layout/PhabricatorTimelineEventView.php b/src/view/layout/PhabricatorTimelineEventView.php
index f7999c7e91..54f226dbbb 100644
--- a/src/view/layout/PhabricatorTimelineEventView.php
+++ b/src/view/layout/PhabricatorTimelineEventView.php
@@ -1,374 +1,376 @@
 <?php
 
 final class PhabricatorTimelineEventView extends AphrontView {
 
   private $userHandle;
   private $title;
   private $icon;
   private $color;
   private $classes = array();
   private $contentSource;
   private $dateCreated;
   private $anchor;
   private $isEditable;
   private $isEdited;
   private $transactionPHID;
   private $isPreview;
   private $eventGroup = array();
 
   public function setTransactionPHID($transaction_phid) {
     $this->transactionPHID = $transaction_phid;
     return $this;
   }
 
   public function getTransactionPHID() {
     return $this->transactionPHID;
   }
 
   public function setIsEdited($is_edited) {
     $this->isEdited = $is_edited;
     return $this;
   }
 
   public function getIsEdited() {
     return $this->isEdited;
   }
 
   public function setIsPreview($is_preview) {
     $this->isPreview = $is_preview;
     return $this;
   }
 
   public function getIsPreview() {
     return $this->isPreview;
   }
 
   public function setIsEditable($is_editable) {
     $this->isEditable = $is_editable;
     return $this;
   }
 
   public function getIsEditable() {
     return $this->isEditable;
   }
 
   public function setDateCreated($date_created) {
     $this->dateCreated = $date_created;
     return $this;
   }
 
   public function getDateCreated() {
     return $this->dateCreated;
   }
 
   public function setContentSource(PhabricatorContentSource $content_source) {
     $this->contentSource = $content_source;
     return $this;
   }
 
   public function getContentSource() {
     return $this->contentSource;
   }
 
   public function setUserHandle(PhabricatorObjectHandle $handle) {
     $this->userHandle = $handle;
     return $this;
   }
 
   public function setAnchor($anchor) {
     $this->anchor = $anchor;
     return $this;
   }
 
   public function setTitle($title) {
     $this->title = $title;
     return $this;
   }
 
   public function addClass($class) {
     $this->classes[] = $class;
     return $this;
   }
 
   public function setIcon($icon) {
     $this->icon = $icon;
     return $this;
   }
 
   public function setColor($color) {
     $this->color = $color;
     return $this;
   }
 
   public function getEventGroup() {
     return array_merge(array($this), $this->eventGroup);
   }
 
   public function addEventToGroup(PhabricatorTimelineEventView $event) {
     $this->eventGroup[] = $event;
     return $this;
   }
 
   protected function renderEventTitle($is_first_event, $force_icon) {
     $title = $this->title;
     if (($title === null) && !$this->hasChildren()) {
       $title = '';
     }
 
     if ($is_first_event) {
       $extra = array();
       $is_first_extra = true;
       foreach ($this->getEventGroup() as $event) {
-        $extra[] = $this->renderExtra($is_first_extra);
+        $extra[] = $event->renderExtra($is_first_extra);
         $is_first_extra = false;
       }
+      $extra = array_reverse($extra);
+      $extra = array_mergev($extra);
       $extra = phutil_tag(
         'span',
         array(
           'class' => 'phabricator-timeline-extra',
         ),
-        phutil_implode_html(" \xC2\xB7 ", array_mergev($extra)));
+        phutil_implode_html(" \xC2\xB7 ", $extra));
     } else {
       $extra = null;
     }
 
     if ($title !== null || $extra) {
       $title_classes = array();
       $title_classes[] = 'phabricator-timeline-title';
 
       $icon = null;
       if ($this->icon || $force_icon) {
         $title_classes[] = 'phabricator-timeline-title-with-icon';
       }
 
       if ($this->icon) {
         $fill_classes = array();
         $fill_classes[] = 'phabricator-timeline-icon-fill';
         if ($this->color) {
           $fill_classes[] = 'phabricator-timeline-icon-fill-'.$this->color;
         }
 
         $icon = phutil_tag(
           'span',
           array(
             'class' => implode(' ', $fill_classes),
           ),
           phutil_tag(
             'span',
             array(
               'class' => 'phabricator-timeline-icon sprite-icons '.
                          'icons-'.$this->icon.'-white',
             ),
             ''));
       }
 
       $title = phutil_tag(
         'div',
         array(
           'class' => implode(' ', $title_classes),
         ),
         array($icon, $title, $extra));
     }
 
     return $title;
   }
 
   public function render() {
 
     $events = $this->getEventGroup();
 
     // Move events with icons first.
     $icon_keys = array();
     foreach ($this->getEventGroup() as $key => $event) {
       if ($event->icon) {
         $icon_keys[] = $key;
       }
     }
     $events = array_select_keys($events, $icon_keys) + $events;
     $force_icon = (bool)$icon_keys;
 
     $group_titles = array();
     $group_children = array();
     $is_first_event = true;
     foreach ($events as $event) {
       $group_titles[] = $event->renderEventTitle($is_first_event, $force_icon);
       $is_first_event = false;
       if ($event->hasChildren()) {
         $group_children[] = $event->renderChildren();
       }
     }
 
     $wedge = phutil_tag(
       'div',
       array(
         'class' => 'phabricator-timeline-wedge phabricator-timeline-border',
       ),
       '');
 
     $image_uri = $this->userHandle->getImageURI();
     $image = phutil_tag(
       'div',
       array(
         'style' => 'background-image: url('.$image_uri.')',
         'class' => 'phabricator-timeline-image',
       ),
       '');
 
     $content_classes = array();
     $content_classes[] = 'phabricator-timeline-content';
 
     $classes = array();
     $classes[] = 'phabricator-timeline-event-view';
     if ($group_children) {
       $classes[] = 'phabricator-timeline-major-event';
       $content = phutil_tag(
         'div',
         array(
           'class' => 'phabricator-timeline-inner-content',
         ),
         array(
           $group_titles,
           phutil_tag(
             'div',
             array(
               'class' => 'phabricator-timeline-core-content',
             ),
             $group_children),
         ));
     } else {
       $classes[] = 'phabricator-timeline-minor-event';
       $content = $group_titles;
     }
 
     $content = phutil_tag(
       'div',
       array(
         'class' => 'phabricator-timeline-group phabricator-timeline-border',
       ),
       $content);
 
     $content = phutil_tag(
       'div',
       array(
         'class' => implode(' ', $content_classes),
       ),
       array($image, $wedge, $content));
 
     $outer_classes = $this->classes;
     $outer_classes[] = 'phabricator-timeline-shell';
     $color = null;
     foreach ($this->getEventGroup() as $event) {
       if ($event->color) {
         $color = $event->color;
         break;
       }
     }
 
     if ($color) {
       $outer_classes[] = 'phabricator-timeline-'.$color;
     }
 
     $sigil = null;
     $meta = null;
     if ($this->getTransactionPHID()) {
       $sigil = 'transaction';
       $meta = array(
         'phid' => $this->getTransactionPHID(),
         'anchor' => $this->anchor,
       );
     }
 
     return javelin_tag(
       'div',
       array(
         'class' => implode(' ', $outer_classes),
         'id' => $this->anchor ? 'anchor-'.$this->anchor : null,
         'sigil' => $sigil,
         'meta' => $meta,
       ),
       phutil_tag(
         'div',
         array(
           'class' => implode(' ', $classes),
         ),
         $content));
   }
 
   private function renderExtra($is_first_extra) {
     $extra = array();
 
     if ($this->getIsPreview()) {
       $extra[] = pht('PREVIEW');
     } else {
       $xaction_phid = $this->getTransactionPHID();
 
       if ($this->getIsEdited()) {
         $extra[] = javelin_tag(
           'a',
           array(
             'href'  => '/transactions/history/'.$xaction_phid.'/',
             'sigil' => 'workflow',
           ),
           pht('Edited'));
       }
 
       if ($this->getIsEditable()) {
         $extra[] = javelin_tag(
           'a',
           array(
             'href'  => '/transactions/edit/'.$xaction_phid.'/',
             'sigil' => 'workflow transaction-edit',
           ),
           pht('Edit'));
       }
 
       if ($is_first_extra) {
         $source = $this->getContentSource();
         if ($source) {
           $extra[] = id(new PhabricatorContentSourceView())
             ->setContentSource($source)
             ->setUser($this->getUser())
             ->render();
         }
 
         $date_created = null;
         foreach ($this->getEventGroup() as $event) {
           if ($event->getDateCreated()) {
             if ($date_created === null) {
               $date_created = $event->getDateCreated();
             } else {
               $date_created = min($event->getDateCreated(), $date_created);
             }
           }
         }
 
         if ($date_created) {
           $date = phabricator_datetime(
             $this->getDateCreated(),
             $this->getUser());
           if ($this->anchor) {
             Javelin::initBehavior('phabricator-watch-anchor');
 
             $anchor = id(new PhabricatorAnchorView())
               ->setAnchorName($this->anchor)
               ->render();
 
             $date = array(
               $anchor,
               phutil_tag(
                 'a',
                 array(
                   'href' => '#'.$this->anchor,
                 ),
                 $date),
             );
           }
           $extra[] = $date;
         }
       }
     }
 
     return $extra;
   }
 
 }