- Fix opening attachments on IE (#1486829)

program/include/rcube_shared.inc

@@ -39,14 +39,16 @@ function send_nocacheing_headers()
 
   header("Expires: ".gmdate("D, d M Y H:i:s")." GMT");
   header("Last-Modified: ".gmdate("D, d M Y H:i:s")." GMT");
-  header("Cache-Control: private, no-cache, must-revalidate, post-check=0, pre-check=0");
-  header("Pragma: no-cache");
   // Request browser to disable DNS prefetching (CVE-2010-0464)
   header("X-DNS-Prefetch-Control: off");
 
   // We need to set the following headers to make downloads work using IE in HTTPS mode.
   if ($OUTPUT->browser->ie && rcube_https_check()) {
     header('Pragma: private');
+    header("Cache-Control: private, must-revalidate");
+  } else {
+    header("Cache-Control: private, no-cache, must-revalidate, post-check=0, pre-check=0");
+    header("Pragma: no-cache");
   }
 }