diff --git a/aegisub/src/ass_dialogue.cpp b/aegisub/src/ass_dialogue.cpp
index 3a5e57efe..2b6b1e231 100644
--- a/aegisub/src/ass_dialogue.cpp
+++ b/aegisub/src/ass_dialogue.cpp
@@ -784,7 +784,7 @@ wxString AssDialogue::GetStrippedText() const {
 }
 /////////
 // Clone
-AssEntry *AssDialogue::Clone() {
+AssEntry *AssDialogue::Clone() const {
 	// Create clone
 	AssDialogue *final = new AssDialogue();
 
diff --git a/aegisub/src/ass_dialogue.h b/aegisub/src/ass_dialogue.h
index f43feb7db..2126e0262 100644
--- a/aegisub/src/ass_dialogue.h
+++ b/aegisub/src/ass_dialogue.h
@@ -196,7 +196,7 @@ public:
 	wxString GetSSAText();
 	bool CollidesWith(AssDialogue *target);					// Checks if two lines collide
 
-	AssEntry *Clone();
+	AssEntry *Clone() const;
 
 	AssDialogue();
 	AssDialogue(wxString data,int version=1);
diff --git a/aegisub/src/ass_entry.cpp b/aegisub/src/ass_entry.cpp
index 05b33a6ba..b6c1753ec 100644
--- a/aegisub/src/ass_entry.cpp
+++ b/aegisub/src/ass_entry.cpp
@@ -119,7 +119,7 @@ wxString AssEntry::GetSSAText() {
 
 /////////
 // Clone
-AssEntry *AssEntry::Clone() {
+AssEntry *AssEntry::Clone() const {
 	// Create clone
 	AssEntry *final = new AssEntry();
 
diff --git a/aegisub/src/ass_entry.h b/aegisub/src/ass_entry.h
index 40745d9c6..15c865ab3 100644
--- a/aegisub/src/ass_entry.h
+++ b/aegisub/src/ass_entry.h
@@ -75,7 +75,7 @@ public:
 	AssEntry(wxString data);
 	virtual ~AssEntry();
 
-	virtual AssEntry *Clone();
+	virtual AssEntry *Clone() const;
 
 	virtual int GetStartMS() const { return StartMS; }
 	virtual int GetEndMS() const { return StartMS; }
diff --git a/aegisub/src/ass_style.cpp b/aegisub/src/ass_style.cpp
index 462383596..7b2c4737a 100644
--- a/aegisub/src/ass_style.cpp
+++ b/aegisub/src/ass_style.cpp
@@ -493,7 +493,7 @@ wxString AssStyle::GetSSAText() {
 
 /////////
 // Clone
-AssEntry *AssStyle::Clone() {
+AssEntry *AssStyle::Clone() const {
 	// Create clone
 	AssStyle *final = new AssStyle();
 
@@ -526,7 +526,7 @@ AssEntry *AssStyle::Clone() {
 	final->strikeout = strikeout;
 	final->underline = underline;
 	final->relativeTo = relativeTo;
-	final->SetEntryData(GetEntryData());
+	final->SetEntryData(const_cast<AssStyle*>(this)->GetEntryData());
 
 	// Return
 	return final;
diff --git a/aegisub/src/ass_style.h b/aegisub/src/ass_style.h
index e0235e9a6..0be3e64c7 100644
--- a/aegisub/src/ass_style.h
+++ b/aegisub/src/ass_style.h
@@ -105,7 +105,7 @@ public:
 	void SetMarginString(const wxString value,int which);	// Sets margin value from a string (0 = left, 1 = right, 2 = vertical/top, 3 = bottom)
 	static void GetEncodings(wxArrayString &encodingStrings);
 
-	AssEntry *Clone();
+	AssEntry *Clone() const;
 	bool IsEqualTo(AssStyle *style);
 
 	AssStyle();