diff --git a/Scintilla.NET.TestApp/FormMain.Designer.cs b/Scintilla.NET.TestApp/FormMain.Designer.cs
index 138f53d..906d137 100644
--- a/Scintilla.NET.TestApp/FormMain.Designer.cs
+++ b/Scintilla.NET.TestApp/FormMain.Designer.cs
@@ -59,6 +59,7 @@ private void InitializeComponent()
 			this.scintilla._ScintillaManagedDragDrop = true;
 			this.scintilla.BorderStyle = ScintillaNET.BorderStyle.Fixed3DVisualStyles;
 			this.scintilla.CaretLineBackColor = System.Drawing.Color.FromArgb(((int)(((byte)(232)))), ((int)(((byte)(232)))), ((int)(((byte)(255)))));
+			this.scintilla.ChangeHistory = ((ScintillaNET.ChangeHistory)((ScintillaNET.ChangeHistory.Enabled | ScintillaNET.ChangeHistory.Markers)));
 			this.scintilla.Dock = System.Windows.Forms.DockStyle.Fill;
 			this.scintilla.FoldLineStripColor = System.Drawing.Color.Gray;
 			this.scintilla.Font = new System.Drawing.Font("Consolas", 10.2F);
@@ -68,6 +69,8 @@ private void InitializeComponent()
 			this.scintilla.ScrollWidth = 1;
 			this.scintilla.Size = new System.Drawing.Size(914, 426);
 			this.scintilla.TabIndex = 2;
+			this.scintilla.SavePointLeft += new System.EventHandler<System.EventArgs>(this.scintilla_SavePointLeft);
+			this.scintilla.SavePointReached += new System.EventHandler<System.EventArgs>(this.scintilla_SavePointReached);
 			this.scintilla.TextChanged += new System.EventHandler(this.scintilla_TextChanged);
 			this.scintilla.KeyDown += new System.Windows.Forms.KeyEventHandler(this.scintilla_KeyDown);
 			// 
@@ -188,6 +191,10 @@ private void InitializeComponent()
 			this.lexersToolStripMenuItem.Size = new System.Drawing.Size(64, 24);
 			this.lexersToolStripMenuItem.Text = "Lexers";
 			// 
+			// saveFileDialog
+			// 
+			this.saveFileDialog.Filter = "All Files|*.*";
+			// 
 			// FormMain
 			// 
 			this.AutoScaleDimensions = new System.Drawing.SizeF(120F, 120F);
diff --git a/Scintilla.NET.TestApp/FormMain.cs b/Scintilla.NET.TestApp/FormMain.cs
index fb8a774..d2cb6d6 100644
--- a/Scintilla.NET.TestApp/FormMain.cs
+++ b/Scintilla.NET.TestApp/FormMain.cs
@@ -10,14 +10,38 @@ namespace ScintillaNET.TestApp;
 
 public partial class FormMain : Form
 {
+    string baseTitle;
+    string? currentFileName = null;
+
+    public string? CurrentFileName
+    {
+        get => this.currentFileName;
+        set
+        {
+            BaseTitle = Path.GetFileName(this.currentFileName = value);
+        }
+    }
+
+    public string BaseTitle
+    {
+        get => this.baseTitle;
+        set
+        {
+            this.Text = (this.baseTitle = value) + (scintilla.Modified ? " *" : "");
+        }
+    }
+
     public FormMain()
     {
         InitializeComponent();
 
+        baseTitle = this.Text;
+
         scintilla.LexerName = "cpp";
 
         SetScintillaStyles(scintilla);
         AdjustLineNumberMargin(scintilla);
+        AdjustMarkerMargin(scintilla);
         AdjustFoldMargin(scintilla);
 
         Version scintillaNetVersion = scintilla.GetType().Assembly.GetName().Version;
@@ -119,6 +143,16 @@ private static void AdjustLineNumberMargin(Scintilla scintilla)
         maxLineNumberCharLengthMap[scintilla] = maxLineNumberCharLength;
     }
 
+    private static void AdjustMarkerMargin(Scintilla scintilla)
+    {
+        scintilla.Margins[1].Width = 16;
+        scintilla.Margins[1].Sensitive = false;
+        //scintilla.Markers[Marker.HistoryRevertedToModified].SetForeColor(Color.Orange);
+        //scintilla.Markers[Marker.HistoryRevertedToModified].SetBackColor(scintilla.Margins[1].BackColor);
+        //scintilla.Markers[Marker.HistoryRevertedToOrigin].SetForeColor(Color.Orange);
+        //scintilla.Markers[Marker.HistoryRevertedToOrigin].SetBackColor(scintilla.Margins[1].BackColor);
+    }
+
     private static void AdjustFoldMargin(Scintilla scintilla)
     {
         // Instruct the lexer to calculate folding
@@ -147,22 +181,28 @@ private static void AdjustFoldMargin(Scintilla scintilla)
         scintilla.Markers[Marker.FolderTail].Symbol = MarkerSymbol.LCorner;
 
         // Enable automatic folding
-        scintilla.AutomaticFold = (AutomaticFold.Show | AutomaticFold.Click | AutomaticFold.Change);
+        scintilla.AutomaticFold = AutomaticFold.Show | AutomaticFold.Click | AutomaticFold.Change;
     }
 
     private void openToolStripMenuItem_Click(object sender, EventArgs e)
     {
         if (openFileDialog.ShowDialog(this) == DialogResult.OK)
         {
-            scintilla.Text = File.ReadAllText(openFileDialog.FileName, Encoding.UTF8);
+            CurrentFileName = openFileDialog.FileName;
+            scintilla.Text = File.ReadAllText(CurrentFileName, Encoding.UTF8);
+            scintilla.ClearChangeHistory();
+            scintilla.SetSavePoint();
         }
     }
 
     private void saveToolStripMenuItem_Click(object sender, EventArgs e)
     {
-        if (saveFileDialog.ShowDialog(this) == DialogResult.OK)
+        if (CurrentFileName is null && saveFileDialog.ShowDialog(this) == DialogResult.OK)
+            CurrentFileName = saveFileDialog.FileName;
+
+        if (CurrentFileName is not null)
         {
-            File.WriteAllText(saveFileDialog.FileName, scintilla.Text, Encoding.UTF8);
+            File.WriteAllText(CurrentFileName, scintilla.Text, Encoding.UTF8);
             scintilla.SetSavePoint();
         }
     }
@@ -195,4 +235,14 @@ private void scintilla_TextChanged(object sender, EventArgs e)
     {
         AdjustLineNumberMargin(scintilla);
     }
+
+    private void scintilla_SavePointLeft(object sender, EventArgs e)
+    {
+        Text = BaseTitle + " *";
+    }
+
+    private void scintilla_SavePointReached(object sender, EventArgs e)
+    {
+        Text = BaseTitle;
+    }
 }
diff --git a/Scintilla.NET.TestApp/Scintilla.NET.TestApp.csproj b/Scintilla.NET.TestApp/Scintilla.NET.TestApp.csproj
index 6c8810d..08a1be7 100644
--- a/Scintilla.NET.TestApp/Scintilla.NET.TestApp.csproj
+++ b/Scintilla.NET.TestApp/Scintilla.NET.TestApp.csproj
@@ -13,6 +13,7 @@
     <PlatformTarget>AnyCPU</PlatformTarget>
     <ApplicationManifest>app.manifest</ApplicationManifest>
     <RootNamespace>ScintillaNET.TestApp</RootNamespace>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
   <ItemGroup>
     <Compile Update="FormMain.cs">