diff --git a/src/mami.js/ui/messages.jsx b/src/mami.js/ui/messages.jsx
index 9c57c78..7d338db 100644
--- a/src/mami.js/ui/messages.jsx
+++ b/src/mami.js/ui/messages.jsx
@@ -11,18 +11,16 @@
 #include ui/emotes.js
 
 Umi.UI.Messages = (function() {
-    let forceUserInfo = false,
-        lastMsgUser = null,
-        lastMsgChannel = null,
-        lastWasTiny = null;
+    let forceUserInfo = false;
+    let lastMsgUser = null;
+    let lastMsgChannel = null;
+    let lastWasTiny = null;
 
     const title = new MamiWindowTitle({
         getName: () => futami.get('title'),
     });
 
-    window.addEventListener('focus', function() {
-        title.clear();
-    });
+    window.addEventListener('focus', () => title.clear());
 
     const botMsgs = {
         'say': { text: '%0' },
@@ -393,7 +391,7 @@ Umi.UI.Messages = (function() {
                 mami.sound.library.play(soundName, soundVolume, soundRate);
             }
 
-            if(window.CustomEvent)
+            if(eBase instanceof HTMLElement)
                 window.dispatchEvent(new CustomEvent('umi:ui:message_add', {
                     detail: {
                         element: eBase,