Fix various issues

Author: MattEqualsCoder

MSUScripter/Services/ProjectService.cs

@@ -25,6 +25,8 @@ public class ProjectService(
 {
     public void SaveMsuProject(MsuProject project, bool isBackup)
     {
+        var previousLastSaveTime = project.LastSaveTime;
+        
         project.LastSaveTime = DateTime.Now;
 
         if (!isBackup)
@@ -79,6 +81,7 @@ public void SaveMsuProject(MsuProject project, bool isBackup)
         }
         else
         {
+            project.LastSaveTime = previousLastSaveTime;
             logger.LogInformation("Saved project backup");
             statusBarService.UpdateStatusBar("Backup Created");
         }

MSUScripter/Views/MsuSongAdvancedPanel.axaml.cs

@@ -32,6 +32,7 @@ protected override void OnLoaded(RoutedEventArgs e)
     {
         base.OnLoaded(e);
         _viewModel = DataContext as MsuSongAdvancedPanelViewModel ?? new MsuSongAdvancedPanelViewModel();
+        Service?.CheckFileErrors(_viewModel);
         _viewModel.ViewModelUpdated += (_, _) =>
         {
             Service?.CheckFileErrors(_viewModel);
@@ -246,6 +247,7 @@ private void AddMsuPcmInfoButton_OnClick(object? sender, RoutedEventArgs e)
             }
 
             _viewModel.AddMsuPcmInfo(treeData);
+            _viewModel.LastModifiedDate = DateTime.Now;
             Service?.CheckFileErrors(_viewModel);
         }
         catch (Exception ex)
@@ -407,6 +409,7 @@ private async void DeleteMsuPcmInfoMenuItem_OnClick(object? sender, RoutedEventA
             }
 
             _viewModel.RemoveMsuPcmInfo(treeData);
+            _viewModel.LastModifiedDate = DateTime.Now;
             Service?.CheckFileErrors(_viewModel);
         }
         catch (Exception ex)