diff --git a/CHANGELOG b/CHANGELOG
index b2b181d9a..c9495855b 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -33,6 +33,7 @@ CHANGELOG Roundcube Webmail
 - Fix Opera browser detection in javascript (#1490307)
 - Fix so search filter, scope and fields are reset on folder change
 - Fix rows count when messages search fails (#1490266)
+- Fix bug where spellchecking in HTML editor do not work after switching editor type more than once (#1490311)
 
 RELEASE 1.1.0
 -------------
diff --git a/program/js/editor.js b/program/js/editor.js
index d16c0e88d..3b2d65ec2 100644
--- a/program/js/editor.js
+++ b/program/js/editor.js
@@ -65,6 +65,15 @@ function rcube_text_editor(config, id)
     }
   }
 
+  // secure spellchecker requests with Roundcube token
+  // Note: must be registered only once (#1490311)
+  if (!tinymce.registered_request_token) {
+    tinymce.registered_request_token = true;
+    tinymce.util.XHR.on('beforeSend', function(e) {
+      e.xhr.setRequestHeader('X-Roundcube-Request', rcmail.env.request_token);
+    });
+  }
+
   // minimal editor
   if (config.mode == 'identity') {
     $.extend(conf, {
@@ -107,10 +116,6 @@ function rcube_text_editor(config, id)
     ed.on('keypress', function() {
       rcmail.compose_type_activity++;
     });
-    // secure spellchecker requests with Roundcube token
-    tinymce.util.XHR.on('beforeSend', function(e) {
-      e.xhr.setRequestHeader('X-Roundcube-Request', rcmail.env.request_token);
-    });
   };
 
   // textarea identifier