diff --git a/pkg/document/crdt/rga_tree_split.go b/pkg/document/crdt/rga_tree_split.go
index d44251379..fc876f1fd 100644
--- a/pkg/document/crdt/rga_tree_split.go
+++ b/pkg/document/crdt/rga_tree_split.go
@@ -548,9 +548,10 @@ func (s *RGATreeSplit[V]) deleteNodes(
 		var maxCreatedAt *time.Ticket
 		var clientLamportAtChange int64
 		if isVersionVectorEmpty && isMaxCreatedAtMapByActorEmpty {
-			// Local edit - use version vector comparison
+			// Case 1: local editing from json package
 			clientLamportAtChange = time.MaxLamport
 		} else if !isVersionVectorEmpty {
+			// Case 2: from operation with version vector(After v0.5.7)
 			lamport, ok := versionVector.Get(actorID)
 			if ok {
 				clientLamportAtChange = lamport
@@ -558,6 +559,7 @@ func (s *RGATreeSplit[V]) deleteNodes(
 				clientLamportAtChange = 0
 			}
 		} else {
+			// Case 3: from operation without version vector(Before v0.5.6)
 			createdAt, ok := maxCreatedAtMapByActor[actorIDHex]
 			if ok {
 				maxCreatedAt = createdAt
diff --git a/pkg/document/crdt/text.go b/pkg/document/crdt/text.go
index 1b135d198..deaf90eac 100644
--- a/pkg/document/crdt/text.go
+++ b/pkg/document/crdt/text.go
@@ -324,9 +324,10 @@ func (t *Text) Style(
 		var maxCreatedAt *time.Ticket
 		var clientLamportAtChange int64
 		if isVersionVectorEmpty && isMaxCreatedAtMapByActorEmpty {
-			// Local edit - use version vector comparison
+			// Case 1: local editing from json package
 			clientLamportAtChange = time.MaxLamport
 		} else if !isVersionVectorEmpty {
+			// Case 2: from operation with version vector(After v0.5.7)
 			lamport, ok := versionVector.Get(actorID)
 			if ok {
 				clientLamportAtChange = lamport
@@ -334,6 +335,7 @@ func (t *Text) Style(
 				clientLamportAtChange = 0
 			}
 		} else {
+			// Case 3: from operation without version vector(Before v0.5.6)
 			createdAt, ok := maxCreatedAtMapByActor[actorIDHex]
 			if ok {
 				maxCreatedAt = createdAt
diff --git a/pkg/document/crdt/tree.go b/pkg/document/crdt/tree.go
index 3ba8dcb63..a6f19d2dc 100644
--- a/pkg/document/crdt/tree.go
+++ b/pkg/document/crdt/tree.go
@@ -872,10 +872,12 @@ func (t *Tree) collectBetween(
 
 			var maxCreatedAt *time.Ticket
 			var clientLamportAtChange int64
+
 			if isVersionVectorEmpty && isMaxCreatedAtMapByActorEmpty {
-				// Local edit - use version vector comparison
+				// Case 1: local editing from json package
 				clientLamportAtChange = time.MaxLamport
 			} else if !isVersionVectorEmpty {
+				// Case 2: from operation with version vector(After v0.5.7)
 				lamport, ok := versionVector.Get(actorID)
 				if ok {
 					clientLamportAtChange = lamport
@@ -883,6 +885,7 @@ func (t *Tree) collectBetween(
 					clientLamportAtChange = 0
 				}
 			} else {
+				// Case 3: from operation without version vector(Before v0.5.6)
 				createdAt, ok := maxCreatedAtMapByActor[actorIDHex]
 				if ok {
 					maxCreatedAt = createdAt
@@ -1016,9 +1019,10 @@ func (t *Tree) Style(
 		var maxCreatedAt *time.Ticket
 		var clientLamportAtChange int64
 		if isVersionVectorEmpty && isMaxCreatedAtMapByActorEmpty {
-			// Local edit - use version vector comparison
+			// Case 1: local editing from json package
 			clientLamportAtChange = time.MaxLamport
 		} else if !isVersionVectorEmpty {
+			// Case 2: from operation with version vector(After v0.5.7)
 			lamport, ok := versionVector.Get(actorID)
 			if ok {
 				clientLamportAtChange = lamport
@@ -1026,6 +1030,7 @@ func (t *Tree) Style(
 				clientLamportAtChange = 0
 			}
 		} else {
+			// Case 3: from operation without version vector(Before v0.5.6)
 			createdAt, ok := maxCreatedAtMapByActor[actorIDHex]
 			if ok {
 				maxCreatedAt = createdAt
@@ -1088,9 +1093,10 @@ func (t *Tree) RemoveStyle(
 		var maxCreatedAt *time.Ticket
 		var clientLamportAtChange int64
 		if isVersionVectorEmpty && isMaxCreatedAtMapByActorEmpty {
-			// Local edit - use version vector comparison
+			// Case 1: local editing from json package
 			clientLamportAtChange = time.MaxLamport
 		} else if !isVersionVectorEmpty {
+			// Case 2: from operation with version vector(After v0.5.7)
 			lamport, ok := versionVector.Get(actorID)
 			if ok {
 				clientLamportAtChange = lamport
@@ -1098,6 +1104,7 @@ func (t *Tree) RemoveStyle(
 				clientLamportAtChange = 0
 			}
 		} else {
+			// Case 3: from operation without version vector(Before v0.5.6)
 			createdAt, ok := maxCreatedAtMapByActor[actorIDHex]
 			if ok {
 				maxCreatedAt = createdAt