diff --git a/moffy-samples-gtk4-run.cabal b/moffy-samples-gtk4-run.cabal
--- a/moffy-samples-gtk4-run.cabal
+++ b/moffy-samples-gtk4-run.cabal
@@ -5,7 +5,7 @@
 -- see: https://github.com/sol/hpack
 
 name:           moffy-samples-gtk4-run
-version:        0.2.1.2
+version:        0.2.1.3
 synopsis:       Package to run moffy samples - Gtk4 version
 description:    Please see the README on GitHub at <https://github.com/YoshikuniJujo/moffy-samples-gtk4-run#readme>
 category:       Control
diff --git a/src/Control/Moffy/Samples/Followbox/Run/Gtk4.hs b/src/Control/Moffy/Samples/Followbox/Run/Gtk4.hs
--- a/src/Control/Moffy/Samples/Followbox/Run/Gtk4.hs
+++ b/src/Control/Moffy/Samples/Followbox/Run/Gtk4.hs
@@ -8,12 +8,16 @@
 module Control.Moffy.Samples.Followbox.Run.Gtk4 (
 	runFollowbox, runFollowbox' ) where
 
+import Prelude hiding (break)
+
 import Control.Arrow
-import Control.Concurrent
+import Control.Monad
 import Control.Moffy
+import Control.Moffy.Samples.Event.Delete
 import Control.Moffy.Samples.Event.CalcTextExtents
 import Control.Moffy.Samples.Handle.TChan
 import Control.Moffy.Samples.Run.TChan
+import Control.Concurrent
 import Control.Concurrent.STM
 import Data.Type.Set ((:-), (:+:), pattern Nil)
 import Data.Type.Flip
@@ -38,7 +42,8 @@
 import Control.Moffy.Samples.Event.Area qualified as A
 
 runFollowbox :: String -> Sig s FollowboxEv T.View () -> IO ()
-runFollowbox brws sig = runFollowbox_ brws Nothing $ viewToView <$%> sig
+runFollowbox brws sig = runFollowbox_ brws Nothing . void
+	$ viewToView <$%> sig `break` deleteEvent `break` checkTerminate
 
 runFollowbox' :: String -> Sig s FollowboxEv ([(Int, Maybe Area)], T.View) () -> IO ()
 runFollowbox' brws sig = runFollowbox_' brws Nothing $ (second viewToView) <$%> sig