diff --git a/resources/celerity/map.php b/resources/celerity/map.php
index 2355f46174..365b256326 100644
--- a/resources/celerity/map.php
+++ b/resources/celerity/map.php
@@ -437,7 +437,7 @@ return array(
     'rsrc/js/application/search/behavior-reorder-profile-menu-items.js' => 'e2e0a072',
     'rsrc/js/application/search/behavior-reorder-queries.js' => 'e9581f08',
     'rsrc/js/application/slowvote/behavior-slowvote-embed.js' => '887ad43f',
-    'rsrc/js/application/transactions/behavior-comment-actions.js' => '06460e71',
+    'rsrc/js/application/transactions/behavior-comment-actions.js' => '0300eae6',
     'rsrc/js/application/transactions/behavior-reorder-configs.js' => 'd7a74243',
     'rsrc/js/application/transactions/behavior-reorder-fields.js' => 'b59e1e96',
     'rsrc/js/application/transactions/behavior-show-older-transactions.js' => '94c65b72',
@@ -594,7 +594,7 @@ return array(
     'javelin-behavior-bulk-job-reload' => 'edf8a145',
     'javelin-behavior-calendar-month-view' => 'fe33e256',
     'javelin-behavior-choose-control' => '327a00d1',
-    'javelin-behavior-comment-actions' => '06460e71',
+    'javelin-behavior-comment-actions' => '0300eae6',
     'javelin-behavior-config-reorder-fields' => 'b6993408',
     'javelin-behavior-conpherence-drag-and-drop-photo' => 'cf86d16a',
     'javelin-behavior-conpherence-menu' => '1d45c74d',
@@ -931,6 +931,15 @@ return array(
       'javelin-dom',
       'phabricator-keyboard-shortcut',
     ),
+    '0300eae6' => array(
+      'javelin-behavior',
+      'javelin-stratcom',
+      'javelin-workflow',
+      'javelin-dom',
+      'phuix-form-control-view',
+      'phuix-icon-view',
+      'javelin-behavior-phabricator-gesture',
+    ),
     '05270951' => array(
       'javelin-util',
       'javelin-magical-init',
@@ -945,15 +954,6 @@ return array(
       'aphront-typeahead-control-css',
       'phui-tag-view-css',
     ),
-    '06460e71' => array(
-      'javelin-behavior',
-      'javelin-stratcom',
-      'javelin-workflow',
-      'javelin-dom',
-      'phuix-form-control-view',
-      'phuix-icon-view',
-      'javelin-behavior-phabricator-gesture',
-    ),
     '065227cc' => array(
       'javelin-behavior',
       'javelin-dom',
diff --git a/src/applications/draft/storage/PhabricatorVersionedDraft.php b/src/applications/draft/storage/PhabricatorVersionedDraft.php
index 2840a4249c..0daf13e8c5 100644
--- a/src/applications/draft/storage/PhabricatorVersionedDraft.php
+++ b/src/applications/draft/storage/PhabricatorVersionedDraft.php
@@ -55,11 +55,27 @@ final class PhabricatorVersionedDraft extends PhabricatorDraftDAO {
       return $draft;
     }
 
-    return id(new PhabricatorVersionedDraft())
-      ->setObjectPHID($object_phid)
-      ->setAuthorPHID($viewer_phid)
-      ->setVersion((int)$version)
-      ->save();
+    try {
+      return id(new self())
+        ->setObjectPHID($object_phid)
+        ->setAuthorPHID($viewer_phid)
+        ->setVersion((int)$version)
+        ->save();
+    } catch (AphrontDuplicateKeyQueryException $ex) {
+      $duplicate_exception = $ex;
+    }
+
+    // In rare cases we can race ourselves, and at one point there was a bug
+    // which caused the browser to submit two preview requests at exactly
+    // the same time. If the insert failed with a duplicate key exception,
+    // try to load the colliding row to recover from it.
+
+    $draft = self::loadDraft($object_phid, $viewer_phid);
+    if ($draft) {
+      return $draft;
+    }
+
+    throw $duplicate_exception;
   }
 
   public static function purgeDrafts(
diff --git a/webroot/rsrc/js/application/transactions/behavior-comment-actions.js b/webroot/rsrc/js/application/transactions/behavior-comment-actions.js
index 87cb80c74a..a28a6b7ca2 100644
--- a/webroot/rsrc/js/application/transactions/behavior-comment-actions.js
+++ b/webroot/rsrc/js/application/transactions/behavior-comment-actions.js
@@ -176,17 +176,28 @@ JX.behavior('comment-actions', function(config) {
     JX.DOM.listen(form_node, 'shouldRefresh', null, always_trigger);
     request.start();
 
+    var old_device = JX.Device.getDevice();
+
     var ondevicechange = function() {
+      var new_device = JX.Device.getDevice();
+
       var panel = JX.$(config.panelID);
-      if (JX.Device.getDevice() == 'desktop') {
+      if (new_device == 'desktop') {
         request.setRateLimit(500);
-        always_trigger();
+
+        // Force an immediate refresh if we switched from another device type
+        // to desktop.
+        if (old_device != new_device) {
+          always_trigger();
+        }
       } else {
         // On mobile, don't show live previews and only save drafts every
         // 10 seconds.
         request.setRateLimit(10000);
         JX.DOM.hide(panel);
       }
+
+      old_device = new_device;
     };
 
     ondevicechange();