diff --git a/python-main.js b/python-main.js
index 955a164c..c3bf646d 100644
--- a/python-main.js
+++ b/python-main.js
@@ -433,7 +433,9 @@ function web_editor(config) {
     function setLanguage(lang) {
         TRANSLATIONS.updateLang(lang, function(translations) {
             config.translate = translations;
-            document.getElementsByTagName("HTML")[0].setAttribute("lang", lang);
+            document.getElementsByTagName('HTML')[0].setAttribute('lang', lang);
+            $('ul.tree > li > a').removeClass('is-selected');
+            $('#'+lang).addClass('is-selected'); 
         });
     }
 
diff --git a/static/css/style.css b/static/css/style.css
index f24c125f..1d3d2f8d 100644
--- a/static/css/style.css
+++ b/static/css/style.css
@@ -950,6 +950,9 @@ ul.tree li:before {
 ul.tree li:last-child:before {
     border-left: 1px solid rgb(100, 100, 100);
 }
+.is-selected {
+    font-weight: bold;
+}
 
 #webusb-flashing-loader {
   border: .2em solid #eee;