From a6c5cdde2bd1bcba82cbfde0d324129124e5366c Mon Sep 17 00:00:00 2001
From: Leonardo Zide <leozide@users.noreply.github.com>
Date: Mon, 23 Feb 2026 22:42:33 -0800
Subject: [PATCH] Fixed selection marking files modified.

---
 common/lc_model.cpp | 24 ++++++++++++++++++++++++
 common/lc_model.h   | 23 +++++++----------------
 2 files changed, 31 insertions(+), 16 deletions(-)

diff --git a/common/lc_model.cpp b/common/lc_model.cpp
index 7c5b73ce..c6cf9f08 100644
--- a/common/lc_model.cpp
+++ b/common/lc_model.cpp
@@ -2010,6 +2010,30 @@ void lcModel::RevertActionSequence()
 	mActionSequence.clear();
 }
 
+bool lcModel::IsModified() const
+{
+	const lcModelHistoryEntry* FirstModifyAction = GetFirstUndoChange();
+	
+	if (!FirstModifyAction)
+		return mSavedHistory != nullptr;
+	else
+		return mSavedHistory != FirstModifyAction;
+}
+
+void lcModel::SetSaved()
+{
+	mSavedHistory = GetFirstUndoChange();
+}
+
+const lcModelHistoryEntry* lcModel::GetFirstUndoChange() const
+{
+	for (const std::unique_ptr<lcModelHistoryEntry>& UndoEntry : mUndoHistory)
+		if (UndoEntry->ModelActions.size() != 1 || !dynamic_cast<lcModelActionSelection*>(UndoEntry->ModelActions.front().get()))
+			return UndoEntry.get();
+	
+	return nullptr;
+}
+
 void lcModel::SaveCheckpoint(const QString& )
 {
 	/*
diff --git a/common/lc_model.h b/common/lc_model.h
index b420d80d..b0a11900 100644
--- a/common/lc_model.h
+++ b/common/lc_model.h
@@ -131,19 +131,14 @@ public:
 		return mProject;
 	}
 
-	bool IsModified() const
-	{
-		if (mUndoHistory.empty())
-			return mSavedHistory != nullptr;
-		else
-			return mSavedHistory != mUndoHistory.front().get();
-	}
-
 	bool IsActive() const
 	{
 		return mActive;
 	}
-
+	
+	bool IsModified() const;
+	void SetSaved();
+	
 	bool GetPieceWorldMatrix(lcPiece* Piece, lcMatrix44& ParentWorldMatrix) const;
 	bool IncludesModel(const lcModel* Model) const;
 	void CreatePieceInfo(Project* Project);
@@ -271,12 +266,7 @@ public:
 	bool LoadInventory(const QByteArray& Inventory);
 	int SplitMPD(QIODevice& Device);
 	void Merge(std::unique_ptr<lcModel> Other);
-
-	void SetSaved()
-	{
-		mSavedHistory = mUndoHistory.empty() ? nullptr : mUndoHistory.front().get();
-	}
-
+	
 	void SetMinifig(const lcMinifig& Minifig);
 	void SetPreviewPieceInfo(PieceInfo* Info, int ColorIndex);
 
@@ -422,6 +412,7 @@ protected:
 	void EndActionSequence(const QString& Description);
 	void DiscardActionSequence();
 	void RevertActionSequence();
+	const lcModelHistoryEntry* GetFirstUndoChange() const;
 
 	void SaveCheckpoint(const QString& Description);
 	void LoadCheckPoint(lcModelHistoryEntry* CheckPoint, bool Apply);
@@ -457,7 +448,7 @@ protected:
 	QStringList mFileLines;
 
 	std::vector<std::unique_ptr<lcModelAction>> mActionSequence;
-	lcModelHistoryEntry* mSavedHistory;
+	const lcModelHistoryEntry* mSavedHistory = nullptr;
 	std::vector<std::unique_ptr<lcModelHistoryEntry>> mUndoHistory;
 	std::vector<std::unique_ptr<lcModelHistoryEntry>> mRedoHistory;