diff --git a/Wino.Calendar.ViewModels/CalendarPageViewModel.cs b/Wino.Calendar.ViewModels/CalendarPageViewModel.cs
index 261b06d1..d75a1f31 100644
--- a/Wino.Calendar.ViewModels/CalendarPageViewModel.cs
+++ b/Wino.Calendar.ViewModels/CalendarPageViewModel.cs
@@ -44,12 +44,12 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
     #region Quick Event Creation
 
     [ObservableProperty]
-    private bool _isQuickEventDialogOpen;
+    public partial bool IsQuickEventDialogOpen { get; set; }
 
     [ObservableProperty]
     [NotifyPropertyChangedFor(nameof(SelectedQuickEventAccountCalendarName))]
     [NotifyCanExecuteChangedFor(nameof(SaveQuickEventCommand))]
-    private AccountCalendarViewModel _selectedQuickEventAccountCalendar;
+    public partial AccountCalendarViewModel SelectedQuickEventAccountCalendar { get; set; }
 
     public string SelectedQuickEventAccountCalendarName
     {
@@ -60,41 +60,62 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
     }
 
     [ObservableProperty]
-    private List<string> _hourSelectionStrings;
+    public partial List<string> HourSelectionStrings { get; set; }
 
     // To be able to revert the values when the user enters an invalid time.
     private string _previousSelectedStartTimeString;
     private string _previousSelectedEndTimeString;
 
     [ObservableProperty]
-    private DateTime? _selectedQuickEventDate;
-
-    [ObservableProperty]
-    private bool _isAllDay;
+    [NotifyCanExecuteChangedFor(nameof(SaveQuickEventCommand))]
+    public partial DateTime? SelectedQuickEventDate { get; set; }
 
     [ObservableProperty]
     [NotifyCanExecuteChangedFor(nameof(SaveQuickEventCommand))]
-    private string _selectedStartTimeString;
+    public partial bool IsAllDay { get; set; }
 
     [ObservableProperty]
     [NotifyCanExecuteChangedFor(nameof(SaveQuickEventCommand))]
-    private string _selectedEndTimeString;
-
-    [ObservableProperty]
-    private string _location;
+    public partial string SelectedStartTimeString { get; set; }
 
     [ObservableProperty]
     [NotifyCanExecuteChangedFor(nameof(SaveQuickEventCommand))]
-    private string _eventName;
+    public partial string SelectedEndTimeString { get; set; }
+
+    [ObservableProperty]
+    public partial string Location { get; set; }
+
+    [ObservableProperty]
+    [NotifyCanExecuteChangedFor(nameof(SaveQuickEventCommand))]
+    public partial string EventName { get; set; }
 
     public DateTime QuickEventStartTime => SelectedQuickEventDate.Value.Date.Add(CurrentSettings.GetTimeSpan(SelectedStartTimeString).Value);
     public DateTime QuickEventEndTime => SelectedQuickEventDate.Value.Date.Add(CurrentSettings.GetTimeSpan(SelectedEndTimeString).Value);
 
-    public bool CanSaveQuickEvent => SelectedQuickEventAccountCalendar != null &&
-                                    !string.IsNullOrWhiteSpace(EventName) &&
-                                    !string.IsNullOrWhiteSpace(SelectedStartTimeString) &&
-                                    !string.IsNullOrWhiteSpace(SelectedEndTimeString) &&
-                                    QuickEventEndTime > QuickEventStartTime;
+    public bool CanSaveQuickEvent
+    {
+        get
+        {
+            if (SelectedQuickEventAccountCalendar == null ||
+                SelectedQuickEventDate == null ||
+                string.IsNullOrWhiteSpace(EventName) ||
+                string.IsNullOrWhiteSpace(SelectedStartTimeString) ||
+                string.IsNullOrWhiteSpace(SelectedEndTimeString))
+            {
+                return false;
+            }
+
+            var startTime = CurrentSettings.GetTimeSpan(SelectedStartTimeString);
+            var endTime = CurrentSettings.GetTimeSpan(SelectedEndTimeString);
+
+            if (!startTime.HasValue || !endTime.HasValue)
+            {
+                return false;
+            }
+
+            return IsAllDay || endTime > startTime;
+        }
+    }
 
     #endregion
 
@@ -152,7 +173,7 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
     private long _pageLifetimeVersion;
 
     [ObservableProperty]
-    private CalendarSettings _currentSettings;
+    public partial CalendarSettings CurrentSettings { get; set; }
 
     public IStatePersistanceService StatePersistanceService { get; }
     public IAccountCalendarStateService AccountCalendarStateService { get; }
@@ -1129,6 +1150,8 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
     {
         if (value)
         {
+            _previousSelectedStartTimeString = SelectedStartTimeString;
+            _previousSelectedEndTimeString = SelectedEndTimeString;
             SelectedStartTimeString = HourSelectionStrings.FirstOrDefault();
             SelectedEndTimeString = HourSelectionStrings.FirstOrDefault();
         }
@@ -1147,7 +1170,7 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
         {
             SelectedStartTimeString = _previousSelectedStartTimeString;
         }
-        else if (IsAllDay)
+        else if (!IsAllDay)
         {
             _previousSelectedStartTimeString = newValue;
         }
@@ -1159,9 +1182,9 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
 
         if (parsedTime == null)
         {
-            SelectedEndTimeString = _previousSelectedStartTimeString;
+            SelectedEndTimeString = _previousSelectedEndTimeString;
         }
-        else if (IsAllDay)
+        else if (!IsAllDay)
         {
             _previousSelectedEndTimeString = newValue;
         }
diff --git a/Wino.Mail.WinUI/Services/NavigationService.cs b/Wino.Mail.WinUI/Services/NavigationService.cs
index 7995e4ec..2f533165 100644
--- a/Wino.Mail.WinUI/Services/NavigationService.cs
+++ b/Wino.Mail.WinUI/Services/NavigationService.cs
@@ -303,6 +303,8 @@ public class NavigationService : NavigationServiceBase, INavigationService
 
         if (innerShellFrame != null)
         {
+            PruneInnerShellBackStackForMode(innerShellFrame, currentApplicationMode);
+
             // Calendar navigations.
             if (currentApplicationMode == WinoApplicationMode.Calendar)
             {
@@ -514,29 +516,42 @@ public class NavigationService : NavigationServiceBase, INavigationService
     private void GoBackInternal(Core.Domain.Enums.NavigationTransitionEffect slideEffect = Core.Domain.Enums.NavigationTransitionEffect.FromRight)
     {
         var innerShellFrame = GetCoreFrameInternal(NavigationReferenceFrame.InnerShellFrame);
+        var currentApplicationMode = _statePersistanceService.ApplicationMode;
 
-        if (_statePersistanceService.ApplicationMode == WinoApplicationMode.Settings &&
+        if (currentApplicationMode == WinoApplicationMode.Settings &&
             _statePersistanceService.HasCurrentModeBackStack)
         {
             WeakReferenceMessenger.Default.Send(new BackBreadcrumNavigationRequested(slideEffect));
             return;
         }
 
-        if (_statePersistanceService.ApplicationMode == WinoApplicationMode.Settings &&
+        if (currentApplicationMode == WinoApplicationMode.Settings &&
             innerShellFrame?.Content is SettingsPage)
         {
             return;
         }
 
-        if (_statePersistanceService.ApplicationMode == WinoApplicationMode.Calendar && innerShellFrame?.CanGoBack == true)
+        if (innerShellFrame != null)
         {
-            innerShellFrame.GoBack();
-            UpdateCurrentModeBackStackState(innerShellFrame);
+            PruneInnerShellBackStackForMode(innerShellFrame, currentApplicationMode);
+        }
+
+        if (currentApplicationMode == WinoApplicationMode.Calendar)
+        {
+            if (innerShellFrame?.CanGoBack == true)
+            {
+                innerShellFrame.GoBack();
+                UpdateCurrentModeBackStackState(innerShellFrame);
+            }
+            else if (innerShellFrame != null && innerShellFrame.Content?.GetType() != typeof(CalendarPage))
+            {
+                NavigateToCalendarRoot(innerShellFrame);
+            }
 
             // Calendar mode: Navigate back from EventDetailsPage
             _statePersistanceService.IsEventDetailsVisible = false;
         }
-        else if (_statePersistanceService.ApplicationMode == WinoApplicationMode.Mail)
+        else if (currentApplicationMode == WinoApplicationMode.Mail)
         {
             if (_statePersistanceService.IsReadingMail && _statePersistanceService.IsReaderNarrowed)
             {
@@ -576,6 +591,51 @@ public class NavigationService : NavigationServiceBase, INavigationService
                                                            innerShellFrame?.CanGoBack == true;
     }
 
+    private void PruneInnerShellBackStackForMode(Frame frame, WinoApplicationMode mode)
+    {
+        for (int i = frame.BackStack.Count - 1; i >= 0; i--)
+        {
+            var backStackEntry = frame.BackStack[i];
+
+            if (!IsPageTypeAllowedInMode(mode, backStackEntry.SourcePageType))
+            {
+                frame.BackStack.RemoveAt(i);
+            }
+        }
+    }
+
+    private bool IsPageTypeAllowedInMode(WinoApplicationMode mode, Type? pageType)
+    {
+        if (pageType == null)
+            return false;
+
+        foreach (var page in Enum.GetValues<WinoPage>())
+        {
+            if (page == WinoPage.None)
+                continue;
+
+            if (GetPageType(page) == pageType)
+                return IsPageAllowedInMode(mode, page);
+        }
+
+        return false;
+    }
+
+    private void NavigateToCalendarRoot(Frame frame)
+    {
+        if (!frame.Navigate(typeof(CalendarPage), new CalendarPageNavigationArgs
+        {
+            RequestDefaultNavigation = true
+        }, GetNavigationTransitionInfo(NavigationTransitionType.None)))
+        {
+            return;
+        }
+
+        frame.BackStack.Clear();
+        frame.ForwardStack.Clear();
+        UpdateCurrentModeBackStackState(frame);
+    }
+
     // Standalone EML viewer.
     //public void NavigateRendering(MimeMessageInformation mimeMessageInformation, NavigationTransitionType transition = NavigationTransitionType.None)
     //{