diff --git a/Wino.Calendar.ViewModels/CalendarPageViewModel.cs b/Wino.Calendar.ViewModels/CalendarPageViewModel.cs
index d154ce49..a8ffb1a7 100644
--- a/Wino.Calendar.ViewModels/CalendarPageViewModel.cs
+++ b/Wino.Calendar.ViewModels/CalendarPageViewModel.cs
@@ -902,6 +902,21 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
         }
     }
 
+    private void UpdateCalendarItemBusyState(Guid calendarItemId, bool isBusy)
+    {
+        var calendarItems = DayRanges
+            .SelectMany(a => a.CalendarDays)
+            .Select(b => b.EventsCollection.GetCalendarItem(calendarItemId))
+            .Where(c => c != null)
+            .OfType<CalendarItemViewModel>()
+            .Distinct();
+
+        foreach (var item in calendarItems)
+        {
+            item.IsBusy = isBusy;
+        }
+    }
+
     public void Receive(CalendarItemTappedMessage message)
     {
         if (message.CalendarItemViewModel == null) return;
@@ -970,6 +985,15 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
 
         await ExecuteUIThread(() =>
         {
+            if (source == CalendarItemUpdateSource.ClientUpdated)
+            {
+                UpdateCalendarItemBusyState(calendarItem.Id, true);
+            }
+            else if (source == CalendarItemUpdateSource.ClientReverted || source == CalendarItemUpdateSource.Server)
+            {
+                UpdateCalendarItemBusyState(calendarItem.Id, false);
+            }
+
             // Update existing items in-place where the item should remain
             foreach (var calendarDay in currentDaysWithItem)
             {
@@ -977,6 +1001,15 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
                 {
                     // Item should stay in this day - update in-place
                     calendarDay.EventsCollection.UpdateCalendarItem(calendarItem);
+
+                    if (source == CalendarItemUpdateSource.Server)
+                    {
+                        var existingViewModel = calendarDay.EventsCollection.GetCalendarItem(calendarItem.Id) as CalendarItemViewModel;
+                        if (existingViewModel != null)
+                        {
+                            existingViewModel.IsBusy = false;
+                        }
+                    }
                 }
                 else
                 {
@@ -1069,7 +1102,10 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
 
         foreach (var calendarDay in allDaysForEvent)
         {
-            var calendarItemViewModel = new CalendarItemViewModel(calendarItem);
+            var calendarItemViewModel = new CalendarItemViewModel(calendarItem)
+            {
+                IsBusy = string.IsNullOrEmpty(calendarItem.RemoteEventId)
+            };
 
             await ExecuteUIThread(() =>
             {
diff --git a/Wino.Calendar.ViewModels/Data/CalendarItemViewModel.cs b/Wino.Calendar.ViewModels/Data/CalendarItemViewModel.cs
index f0771b1e..409fdb9a 100644
--- a/Wino.Calendar.ViewModels/Data/CalendarItemViewModel.cs
+++ b/Wino.Calendar.ViewModels/Data/CalendarItemViewModel.cs
@@ -74,6 +74,9 @@ public partial class CalendarItemViewModel : ObservableObject, ICalendarItem, IC
     [ObservableProperty]
     public partial bool IsSelected { get; set; }
 
+    [ObservableProperty]
+    public partial bool IsBusy { get; set; }
+
     /// <summary>
     /// The period of the day where this item is currently being displayed.
     /// Used for multi-day event title formatting.
diff --git a/Wino.Calendar.ViewModels/EventDetailsPageViewModel.cs b/Wino.Calendar.ViewModels/EventDetailsPageViewModel.cs
index 2e91dd0e..c13bd876 100644
--- a/Wino.Calendar.ViewModels/EventDetailsPageViewModel.cs
+++ b/Wino.Calendar.ViewModels/EventDetailsPageViewModel.cs
@@ -191,7 +191,10 @@ public partial class EventDetailsPageViewModel : CalendarBaseViewModel
             if (source == CalendarItemUpdateSource.ClientUpdated || source == CalendarItemUpdateSource.ClientReverted)
             {
                 var previousAttendees = CurrentEvent?.Attendees?.ToList() ?? [];
-                CurrentEvent = new CalendarItemViewModel(calendarItem);
+                CurrentEvent = new CalendarItemViewModel(calendarItem)
+                {
+                    IsBusy = source == CalendarItemUpdateSource.ClientUpdated
+                };
 
                 foreach (var attendee in previousAttendees)
                 {
diff --git a/Wino.Core.Domain/Interfaces/ICalendarItemViewModel.cs b/Wino.Core.Domain/Interfaces/ICalendarItemViewModel.cs
index 4600a3b2..55a91f68 100644
--- a/Wino.Core.Domain/Interfaces/ICalendarItemViewModel.cs
+++ b/Wino.Core.Domain/Interfaces/ICalendarItemViewModel.cs
@@ -11,6 +11,8 @@ public interface ICalendarItemViewModel
 {
     bool IsSelected { get; set; }
 
+    bool IsBusy { get; set; }
+
     /// <summary>
     /// The period of the day where this item is currently being displayed.
     /// </summary>
diff --git a/Wino.Mail.WinUI/Controls/Calendar/CalendarItemControl.xaml b/Wino.Mail.WinUI/Controls/Calendar/CalendarItemControl.xaml
index 0c73897d..64ce0b93 100644
--- a/Wino.Mail.WinUI/Controls/Calendar/CalendarItemControl.xaml
+++ b/Wino.Mail.WinUI/Controls/Calendar/CalendarItemControl.xaml
@@ -77,6 +77,18 @@
             Text="{x:Bind CalendarItem.DisplayTitle, Mode=OneWay}"
             TextTrimming="CharacterEllipsis" />
 
+
+        <muxc:ProgressRing
+            x:Name="BusyRing"
+            Width="14"
+            Height="14"
+            Grid.Column="2"
+            Margin="0,2,2,0"
+            HorizontalAlignment="Right"
+            VerticalAlignment="Top"
+            IsActive="False"
+            Visibility="Collapsed" />
+
         <!--  TODO: Event attributes  -->
         <StackPanel
             x:Name="AttributeStack"
@@ -126,6 +138,20 @@
                     </VisualState.Setters>
                 </VisualState>
             </VisualStateGroup>
+            <VisualStateGroup x:Name="BusyStates">
+                <VisualState x:Name="NotBusy" />
+                <VisualState x:Name="Busy">
+                    <VisualState.StateTriggers>
+                        <StateTrigger IsActive="{x:Bind CalendarItem.IsBusy, Mode=OneWay, FallbackValue=False}" />
+                    </VisualState.StateTriggers>
+                    <VisualState.Setters>
+                        <Setter Target="MainBackground.Opacity" Value="0.55" />
+                        <Setter Target="BusyRing.IsActive" Value="True" />
+                        <Setter Target="BusyRing.Visibility" Value="Visible" />
+                    </VisualState.Setters>
+                </VisualState>
+            </VisualStateGroup>
+
             <VisualStateGroup x:Name="EventDurationStates">
                 <!--  Regular event template in the panel.  -->
                 <VisualState x:Name="RegularEvent" />