try this

Author: beto-rodriguez

samples/FluidHostPage.cs

@@ -5,6 +5,7 @@ namespace Sample;
 
 public class FluidHostPage : ContentPage, IFluidHost
 {
+    private int _zIndex = 0;
     private View? _currentView;
     private readonly AbsoluteLayout _root = [];
 
@@ -17,15 +18,11 @@ public FluidHostPage()
 
     }
 
-    private int _zIndex = 0;
-
     public void ShowView(View view)
     {
-        //_ = _root.Children.Remove(_currentView);
-
         view.ZIndex = _zIndex++;
         view.WidthRequest = Width;
-        view.HeightRequest = Width;
+        view.HeightRequest = Height;
 
         _currentView = view;
 

src/FlowNavigation.cs

@@ -148,6 +148,20 @@ private async Task<View> Go(bool isHotReload = false)
         var view = (View?)_services.GetService(targetType) ??
             throw new Exception($"View {targetType.Name} not found");
 
+        _ = view.FadeTo(1);
+
+        string? previousRouteName = null;
+        Type? previousRouteType = null;
+        View? previousView = null;
+
+        if (_activeIndex > 0)
+        {
+            previousRouteName = _navigationStack[_activeIndex - 1].Split('?')[0];
+            previousRouteType = ActiveRoutes[previousRouteName];
+            previousView = (View?)_services.GetService(previousRouteType) ??
+                throw new Exception($"View {previousRouteType.Name} not found");
+        }
+
         if (_activeView is not null)
         {
             _activeView.OnLeaving();
@@ -166,6 +180,7 @@ private async Task<View> Go(bool isHotReload = false)
             }
         }
 
+        _ = (previousView?.FadeTo(0));
         Current?.View.ShowView(view);
 
         if (view is FluidView fluidView)
@@ -201,11 +216,8 @@ private async Task<View> Go(bool isHotReload = false)
                     .ToDouble(VisualElement.WidthRequestProperty, flowView.Width)
                     .ToDouble(VisualElement.HeightRequestProperty, flowView.Height));
 
-                if (_activeIndex > 0)
+                if (previousRouteType is not null)
                 {
-                    var previousRouteName = _navigationStack[_activeIndex - 1].Split('?');
-                    var previousRouteType = ActiveRoutes[previousRouteName[0]];
-
                     _ = fluidView.TransitionView.FlowToResult(previousRouteType);
                     _ = await fluidView.TransitionView.Flow(targetType);
                 }
@@ -214,6 +226,11 @@ private async Task<View> Go(bool isHotReload = false)
             _activeView = fluidView;
         }
 
+        if (previousView is not null)
+        {
+            Current?.View.RemoveView(previousView);
+        }
+
         return view;
     }
 }

src/IFluidHost.cs

@@ -16,7 +16,7 @@ public interface IFluidHost
     double Height { get; }
 
     /// <summary>
-    /// Shows the specified view, null to clear it.
+    /// Shows the specified view.
     /// </summary>
     void ShowView(View view);
 }