diff --git a/CHANGELOG b/CHANGELOG
index 550819880718da0bd3f8b540c9266b3817f4872b..fa8ecbd8c74be7bb460a022d333b522e464a9309 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -11,6 +11,7 @@ v 7.11.0 (unreleased)
   -
   -
   - Improve new project command options (Ben Bodenmiller)
+  - Prevent sending empty messages to HipChat (Chulki Lee)
 
 v 7.10.0 (unreleased)
   - Ignore submodules that are defined in .gitmodules but are checked in as directories.
diff --git a/app/models/project_services/hipchat_service.rb b/app/models/project_services/hipchat_service.rb
index d264a56ebdf496582c6861139b1eb8a789195a1f..07520eab5d13164793824b186ecb693adb4314cd 100644
--- a/app/models/project_services/hipchat_service.rb
+++ b/app/models/project_services/hipchat_service.rb
@@ -50,8 +50,9 @@ class HipchatService < Service
 
   def execute(data)
     return unless supported_events.include?(data[:object_kind])
-
-    gate[room].send('GitLab', create_message(data))
+    message = create_message(data)
+    return unless message.present?
+    gate[room].send('GitLab', message)
   end
 
   private
diff --git a/app/views/projects/_md_preview.html.haml b/app/views/projects/_md_preview.html.haml
index f356a25dbfa23738996debf3fca8d7c94acd4511..b869fd6e12a0f7838919ca86cc498bdd6ca10cc3 100644
--- a/app/views/projects/_md_preview.html.haml
+++ b/app/views/projects/_md_preview.html.haml
@@ -9,5 +9,5 @@
 %div
   .md-write-holder
     = yield
-  .md-preview-holder.hide
+  .md.md-preview-holder.hide
     .js-md-preview{class: (preview_class if defined?(preview_class))}