diff --git a/stumpwm/stumpwmrc b/stumpwm/stumpwmrc
index ca72c41..994c48b 100644
--- a/stumpwm/stumpwmrc
+++ b/stumpwm/stumpwmrc
@@ -363,7 +363,8 @@ script."
 (define-frame-preference "winkel"
   (0 nil t :class "keepassxc")
   (0 nil t :class "Nextcloud")
-  (0 nil t :class "TelegramDesktop"))
+  (0 nil t :class "TelegramDesktop")
+  (0 nil t :class "Microsoft Teams - Preview"))
 
 (define-frame-preference "web"
   (0 nil t :class "Firefox"))