diff --git a/include/class.file.php b/include/class.file.php
index d68a3b11b1f403a4a0aacc1a58db37c61151eb68..a2944c9db95ab97a86d7e05fdc8de547c1b57307 100644
--- a/include/class.file.php
+++ b/include/class.file.php
@@ -200,7 +200,8 @@ class AttachmentFile {
         if ($bk->sendRedirectUrl('inline'))
             return;
         $this->makeCacheable();
-        Http::download($this->getName(), $this->getType() ?: 'application/octet-stream');
+        Http::download($this->getName(), $this->getType() ?: 'application/octet-stream',
+            null, 'inline');
         header('Content-Length: '.$this->getSize());
         $this->sendData(false);
         exit();