Fixed the issue with mail rendering page not getting disposed properly.

Wino.Mail.ViewModels/MailRenderingPageViewModel.cs

@@ -535,7 +535,10 @@ public partial class MailRenderingPageViewModel : MailBaseViewModel,
     {
         base.OnNavigatedFrom(mode, parameters);
 
-        renderCancellationTokenSource.Cancel();
+        renderCancellationTokenSource?.Cancel();
+        renderCancellationTokenSource?.Dispose();
+        renderCancellationTokenSource = null;
+
         CurrentDownloadPercentage = 0d;
 
         initializedMailItemViewModel = null;

Wino.Mail.WinUI/Views/MailRenderingPage.xaml.cs

@@ -14,9 +14,9 @@ using Wino.Core.Domain;
 using Wino.Core.Domain.Enums;
 using Wino.Core.Domain.Interfaces;
 using Wino.Core.Domain.Models.Printing;
-using Wino.Mail.WinUI.Extensions;
 using Wino.Mail.ViewModels.Data;
 using Wino.Mail.WinUI;
+using Wino.Mail.WinUI.Extensions;
 using Wino.Messaging.Client.Mails;
 using Wino.Messaging.Client.Shell;
 using Wino.Views.Abstract;
@@ -149,6 +149,9 @@ public sealed partial class MailRenderingPage : MailRenderingPageAbstract,
         // Disposing the page.
         // Make sure the WebView2 is disposed properly.
 
+        ViewModel.SaveHTMLasPDFFunc = null;
+        ViewModel.DirectPrintFuncAsync = null;
+
         DisposeWebView2();
     }