diff --git a/src/applications/differential/controller/DifferentialInlineCommentEditController.php b/src/applications/differential/controller/DifferentialInlineCommentEditController.php
--- a/src/applications/differential/controller/DifferentialInlineCommentEditController.php
+++ b/src/applications/differential/controller/DifferentialInlineCommentEditController.php
@@ -131,11 +131,26 @@
 
   protected function deleteComment(PhabricatorInlineCommentInterface $inline) {
     $inline->openTransaction();
+
+      $inline->setIsDeleted(1)->save();
       DifferentialDraft::deleteHasDraft(
         $inline->getAuthorPHID(),
         $inline->getRevisionPHID(),
         $inline->getPHID());
-      $inline->delete();
+
+    $inline->saveTransaction();
+  }
+
+  protected function undeleteComment(
+    PhabricatorInlineCommentInterface $inline) {
+    $inline->openTransaction();
+
+      $inline->setIsDeleted(0)->save();
+      DifferentialDraft::markHasDraft(
+        $inline->getAuthorPHID(),
+        $inline->getRevisionPHID(),
+        $inline->getPHID());
+
     $inline->saveTransaction();
   }
 
diff --git a/src/applications/diffusion/controller/DiffusionInlineCommentController.php b/src/applications/diffusion/controller/DiffusionInlineCommentController.php
--- a/src/applications/diffusion/controller/DiffusionInlineCommentController.php
+++ b/src/applications/diffusion/controller/DiffusionInlineCommentController.php
@@ -108,7 +108,12 @@
   }
 
   protected function deleteComment(PhabricatorInlineCommentInterface $inline) {
-    return $inline->delete();
+    $inline->setIsDeleted(1)->save();
+  }
+
+  protected function undeleteComment(
+    PhabricatorInlineCommentInterface $inline) {
+    $inline->setIsDeleted(0)->save();
   }
 
   protected function saveComment(PhabricatorInlineCommentInterface $inline) {
diff --git a/src/infrastructure/diff/PhabricatorInlineCommentController.php b/src/infrastructure/diff/PhabricatorInlineCommentController.php
--- a/src/infrastructure/diff/PhabricatorInlineCommentController.php
+++ b/src/infrastructure/diff/PhabricatorInlineCommentController.php
@@ -12,6 +12,8 @@
     PhabricatorInlineCommentInterface $inline);
   abstract protected function deleteComment(
     PhabricatorInlineCommentInterface $inline);
+  abstract protected function undeleteComment(
+    PhabricatorInlineCommentInterface $inline);
   abstract protected function saveComment(
     PhabricatorInlineCommentInterface $inline);
 
@@ -167,7 +169,12 @@
         $is_delete = ($op == 'delete' || $op == 'refdelete');
 
         $inline = $this->loadCommentForEdit($this->getCommentID());
-        $inline->setIsDeleted((int)$is_delete)->save();
+
+        if ($is_delete) {
+          $this->deleteComment($inline);
+        } else {
+          $this->undeleteComment($inline);
+        }
 
         return $this->buildEmptyResponse();
       case 'edit':