diff --git a/UI/WebServerResources/MailerUI.js b/UI/WebServerResources/MailerUI.js
index 99fcfd3a4..23cab23c3 100644
--- a/UI/WebServerResources/MailerUI.js
+++ b/UI/WebServerResources/MailerUI.js
@@ -1900,7 +1900,7 @@ function configureDragHandles() {
         handle.addInterface(SOGoDragHandlesInterface);
         handle.upperBlock=$("mailboxContent");
         handle.lowerBlock=$("messageContent");
-        handle.upperBlock.observe("handle:resize", onMessageListResize);
+        handle.observe("handle:dragged", onMessageListResize);
     }
 }