diff --git a/moffy-samples-events.cabal b/moffy-samples-events.cabal
--- a/moffy-samples-events.cabal
+++ b/moffy-samples-events.cabal
@@ -5,7 +5,7 @@
 -- see: https://github.com/sol/hpack
 
 name:           moffy-samples-events
-version:        0.1.1.0
+version:        0.2.1.0
 synopsis:       Events for sample codes of moffy
 description:    Please see the README on GitHub at <https://github.com/YoshikuniJujo/moffy-samples-events#readme>
 category:       Control
diff --git a/src/Control/Moffy/Samples/Followbox/Event.hs b/src/Control/Moffy/Samples/Followbox/Event.hs
--- a/src/Control/Moffy/Samples/Followbox/Event.hs
+++ b/src/Control/Moffy/Samples/Followbox/Event.hs
@@ -46,6 +46,8 @@
 
 import Control.Moffy.Samples.Followbox.TypeSynonym (Uri, ErrorMessage)
 
+import Control.Moffy.Samples.Event.Area
+
 ---------------------------------------------------------------------------
 
 -- * STORE AND LOAD JSON OBJECT LIST
@@ -176,7 +178,8 @@
 type SigF s = Sig s FollowboxEv
 type ReactF s r = React s FollowboxEv r
 
-type FollowboxEv = GetThreadId :- LockEv :+: RandomEv :+: DeleteEvent :- MouseEv :+:
+type FollowboxEv = SetArea :- GetArea :-
+	GetThreadId :- LockEv :+: RandomEv :+: DeleteEvent :- MouseEv :+:
 	StoreJsons :- LoadJsons :- HttpGet :- CalcTextExtents :- GetTimeZone :-
 	Browse :- BeginSleep :- EndSleep :- RaiseError :- 'Nil
 
diff --git a/src/Control/Moffy/Samples/Followbox/Handle.hs b/src/Control/Moffy/Samples/Followbox/Handle.hs
--- a/src/Control/Moffy/Samples/Followbox/Handle.hs
+++ b/src/Control/Moffy/Samples/Followbox/Handle.hs
@@ -44,6 +44,11 @@
 
 import Data.OneOrMoreApp as Ooma
 
+import Control.Concurrent.STM
+import Control.Moffy.Samples.Handle.Area qualified as A
+import Control.Moffy.Samples.Event.Area qualified as A
+import Data.Map (Map)
+
 ---------------------------------------------------------------------------
 
 -- * STATE
@@ -101,9 +106,10 @@
 
 handleFollowboxWith ::
 	(Maybe DiffTime -> f -> Handle' IO (CalcTextExtents :- GuiEv)) ->
-	f -> Browser -> Maybe GithubNameToken ->
+	f -> TVar (Map Int (A.Point, A.Point)) -> Browser -> Maybe GithubNameToken ->
 	HandleF IO (GuiEv :+: FollowboxEv)
-handleFollowboxWith h f brws mba = retrySt $
+handleFollowboxWith h f va brws mba = retrySt $
+	liftHandle' (A.handle va) `mergeSt`
 	liftHandle' handleGetThreadId `mergeSt` handleLock `mergeSt`
 	handleRandom `mergeSt`
 	handleStoreJsons `mergeSt` handleLoadJsons `mergeSt`