From d99697f4ae211ffbe5ddd16a5f73ac641a0251de Mon Sep 17 00:00:00 2001
From: Dan Walmsley <dan@walms.co.uk>
Date: Wed, 31 May 2023 12:58:21 +0100
Subject: [PATCH] fixes the overlay popup glitch where it renders at 0,0 before
 applying the offet.

use the media context api to sync with layout and render.
---
 src/Avalonia.Base/Media/MediaContext.cs              | 9 +++++++--
 src/Avalonia.Controls/Primitives/OverlayPopupHost.cs | 8 ++++----
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/Avalonia.Base/Media/MediaContext.cs b/src/Avalonia.Base/Media/MediaContext.cs
index c261dd80b8..a41107360a 100644
--- a/src/Avalonia.Base/Media/MediaContext.cs
+++ b/src/Avalonia.Base/Media/MediaContext.cs
@@ -212,7 +212,12 @@ internal partial class MediaContext : ICompositorScheduler
         }
         while (count > 0);
     }
-    
+
+    /// <summary>
+    /// Executes the <param name="callback">callback</param> in the layout pass that will occur
+    /// immediately before the next rendered frame.
+    /// </summary>
+    /// <param name="callback">Code to execute.</param>
     public void BeginInvokeOnRender(Action callback)
     {
         if (_invokeOnRenderCallbacks == null)
@@ -224,4 +229,4 @@ internal partial class MediaContext : ICompositorScheduler
         if (!_isRendering) 
             ScheduleRender(true);
     }
-}
\ No newline at end of file
+}
diff --git a/src/Avalonia.Controls/Primitives/OverlayPopupHost.cs b/src/Avalonia.Controls/Primitives/OverlayPopupHost.cs
index 2236d87dd1..5dd0f23e8e 100644
--- a/src/Avalonia.Controls/Primitives/OverlayPopupHost.cs
+++ b/src/Avalonia.Controls/Primitives/OverlayPopupHost.cs
@@ -120,11 +120,11 @@ namespace Avalonia.Controls.Primitives
         void IManagedPopupPositionerPopup.MoveAndResize(Point devicePoint, Size virtualSize)
         {
             _lastRequestedPosition = devicePoint;
-            Dispatcher.UIThread.Post(() =>
+            MediaContext.Instance.BeginInvokeOnRender(() =>
             {
-                OverlayLayer.SetLeft(this, _lastRequestedPosition.X);
-                OverlayLayer.SetTop(this, _lastRequestedPosition.Y);
-            }, DispatcherPriority.Render);
+                Canvas.SetLeft(this, _lastRequestedPosition.X);
+                Canvas.SetTop(this, _lastRequestedPosition.Y);
+            });
         }
 
         double IManagedPopupPositionerPopup.Scaling => 1;