unsaved indicator

src/modules/registrypreview/RegistryPreviewUILib/RegistryPreviewMainPage.Events.cs

@@ -112,6 +112,7 @@ private async void OpenButton_Click(object sender, RoutedEventArgs e)
                     case ContentDialogResult.Secondary:
                         // Don't save and continue the file open!
                         saveButton.IsEnabled = false;
+                        UpdateUnsavedFileIndicator(false);
                         break;
                     default:
                         // Don't open the new file!
@@ -143,6 +144,7 @@ private async void OpenButton_Click(object sender, RoutedEventArgs e)
 
                 // disable the Save button as it's a new file
                 saveButton.IsEnabled = false;
+                UpdateUnsavedFileIndicator(false);
 
                 // Restore the event handler as we're loaded
                 MonacoEditor.TextChanged += MonacoEditor_TextChanged;
@@ -193,6 +195,7 @@ private async void RefreshButton_Click(object sender, RoutedEventArgs e)
             UpdateToolBarAndUI(await OpenRegistryFile(_appFileName), true, true);
 
             saveButton.IsEnabled = false;
+            UpdateUnsavedFileIndicator(false);
 
             // restore the TextChanged handler
             MonacoEditor.TextChanged += MonacoEditor_TextChanged;
@@ -355,6 +358,7 @@ private void MonacoEditor_TextChanged(object sender, EventArgs e)
             {
                 RefreshRegistryFile();
                 saveButton.IsEnabled = true;
+                UpdateUnsavedFileIndicator(true);
             });
         }
     }

src/modules/registrypreview/RegistryPreviewUILib/RegistryPreviewMainPage.Utilities.cs

@@ -11,6 +11,7 @@
 using System.Linq;
 using System.Reflection;
 using System.Text;
+using System.Text.RegularExpressions;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.UI.Input;
@@ -22,6 +23,9 @@ namespace RegistryPreviewUILib
 {
     public sealed partial class RegistryPreviewMainPage : Page
     {
+        private static readonly string _usavedFileIndicator = "* ";
+        private static readonly char[] _usavedFileIndicatorChars = [' ', '*'];
+
         private static SemaphoreSlim _dialogSemaphore = new(1);
         private string lastKeyPath;
 
@@ -834,6 +838,7 @@ private async void HandleDirtyClosing(string title, string content, string prima
                     break;
                 case ContentDialogResult.Secondary:
                     // Don't save, and then close!
+                    UpdateUnsavedFileIndicator(false);
                     saveButton.IsEnabled = false;
                     break;
                 default:
@@ -902,6 +907,25 @@ public void ChangeCursor(UIElement uiElement, bool wait)
             type.InvokeMember("ProtectedCursor", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.SetProperty | BindingFlags.Instance, null, uiElement, new object[] { cursor }, CultureInfo.InvariantCulture);
         }
 
+        public void UpdateUnsavedFileIndicator(bool show)
+        {
+            // get and cut current title
+            string currentTitel = Regex.Replace(_mainWindow.Title, APPNAME + @"$|\s-\s" + APPNAME + @"$", string.Empty);
+
+            // verify
+            bool titleContiansIndicator = currentTitel.StartsWith(_usavedFileIndicator, StringComparison.CurrentCultureIgnoreCase);
+
+            // update
+            if (!titleContiansIndicator && show)
+            {
+                _updateWindowTitleFunction(_usavedFileIndicator + currentTitel);
+            }
+            else if (titleContiansIndicator && !show)
+            {
+                _updateWindowTitleFunction(currentTitel.TrimStart(_usavedFileIndicatorChars));
+            }
+        }
+
         /// <summary>
         /// Wrapper method that saves the current file in place, using the current text in editor.
         /// </summary>
@@ -930,6 +954,7 @@ private void SaveFile()
                 streamWriter.Close();
 
                 // only change when the save is successful
+                UpdateUnsavedFileIndicator(false);
                 saveButton.IsEnabled = false;
             }
             catch (UnauthorizedAccessException ex)