diff --git a/src/Avalonia.Base/AvaloniaObjectExtensions.cs b/src/Avalonia.Base/AvaloniaObjectExtensions.cs
index 0c22213d33..b3f41eb420 100644
--- a/src/Avalonia.Base/AvaloniaObjectExtensions.cs
+++ b/src/Avalonia.Base/AvaloniaObjectExtensions.cs
@@ -334,7 +334,7 @@ namespace Avalonia
         /// <typeparamref name="TTarget"/>.
         /// </summary>
         /// <typeparam name="TTarget">The type of the property change sender.</typeparam>
-        /// /// <typeparam name="TValue">The type of the property..</typeparam>
+        /// <typeparam name="TValue">The type of the property.</typeparam>
         /// <param name="observable">The property changed observable.</param>
         /// <param name="action">
         /// The method to call. The parameters are the sender and the event args.
diff --git a/src/Avalonia.Base/Media/EllipseGeometry.cs b/src/Avalonia.Base/Media/EllipseGeometry.cs
index 8211855324..84d74e888e 100644
--- a/src/Avalonia.Base/Media/EllipseGeometry.cs
+++ b/src/Avalonia.Base/Media/EllipseGeometry.cs
@@ -56,6 +56,10 @@ namespace Avalonia.Media
         /// <summary>
         /// Gets or sets a rect that defines the bounds of the ellipse.
         /// </summary>
+        /// <remarks>
+        /// When set, this takes priority over the other properties that define an
+        /// ellipse using a center point and X/Y-axis radii.
+        /// </remarks>
         public Rect Rect
         {
             get => GetValue(RectProperty);
@@ -65,6 +69,10 @@ namespace Avalonia.Media
         /// <summary>
         /// Gets or sets a double that defines the radius in the X-axis of the ellipse.
         /// </summary>
+        /// <remarks>
+        /// In order for this property to be used, <see cref="Rect"/> must not be set
+        /// (equal to the default <see cref="Avalonia.Rect"/> value).
+        /// </remarks>
         public double RadiusX
         {
             get => GetValue(RadiusXProperty);
@@ -74,6 +82,10 @@ namespace Avalonia.Media
         /// <summary>
         /// Gets or sets a double that defines the radius in the Y-axis of the ellipse.
         /// </summary>
+        /// <remarks>
+        /// In order for this property to be used, <see cref="Rect"/> must not be set
+        /// (equal to the default <see cref="Avalonia.Rect"/> value).
+        /// </remarks>
         public double RadiusY
         {
             get => GetValue(RadiusYProperty);
@@ -83,6 +95,10 @@ namespace Avalonia.Media
         /// <summary>
         /// Gets or sets a point that defines the center of the ellipse.
         /// </summary>
+        /// <remarks>
+        /// In order for this property to be used, <see cref="Rect"/> must not be set
+        /// (equal to the default <see cref="Avalonia.Rect"/> value).
+        /// </remarks>
         public Point Center
         {
             get => GetValue(CenterProperty);
@@ -92,7 +108,30 @@ namespace Avalonia.Media
         /// <inheritdoc/>
         public override Geometry Clone()
         {
-            return new EllipseGeometry(Rect);
+            // Note that the ellipse properties are used in two modes:
+            //
+            //  1. Rect-only Mode:
+            //     Directly set the rectangle bounds the ellipse will fill
+            //
+            //  2. Center + Radii Mode:
+            //     Set a center-point and then X/Y-axis radii that are used to
+            //     calculate the rectangle bounds the ellipse will fill.
+            //     This is the only mode supported by WPF.
+            //
+            // Rendering the ellipse will only ever use one of these two modes
+            // based on if the Rect property is set (not equal to default).
+            //
+            // This means it would normally be fine to copy ONLY the Rect property
+            // when it is set. However, while it would render the same, it isn't
+            // a true clone. We want to include all the properties here regardless
+            // of the rendering mode that will eventually be used.
+            return new EllipseGeometry()
+            {
+                Rect = Rect,
+                RadiusX = RadiusX,
+                RadiusY = RadiusY,
+                Center = Center,
+            };
         }
 
         /// <inheritdoc/>
diff --git a/src/Avalonia.Base/Media/TextFormatting/Unicode/BiDiAlgorithm.cs b/src/Avalonia.Base/Media/TextFormatting/Unicode/BiDiAlgorithm.cs
index 3406432ce7..f418d4e14a 100644
--- a/src/Avalonia.Base/Media/TextFormatting/Unicode/BiDiAlgorithm.cs
+++ b/src/Avalonia.Base/Media/TextFormatting/Unicode/BiDiAlgorithm.cs
@@ -687,7 +687,7 @@ namespace Avalonia.Media.TextFormatting.Unicode
         /// <remarks>
         /// This method resolves the sos and eos values for the run
         /// and adds the run to the list
-        /// /// </remarks>
+        /// </remarks>
         /// <param name="start">The index of the start of the run (in x9 removed units)</param>
         /// <param name="length">The length of the run (in x9 removed units)</param>
         /// <param name="level">The level of the run</param>
diff --git a/src/Avalonia.Base/Platform/IPlatformRenderInterface.cs b/src/Avalonia.Base/Platform/IPlatformRenderInterface.cs
index 6f62c3be1d..57fedb3d69 100644
--- a/src/Avalonia.Base/Platform/IPlatformRenderInterface.cs
+++ b/src/Avalonia.Base/Platform/IPlatformRenderInterface.cs
@@ -18,7 +18,7 @@ namespace Avalonia.Platform
         /// Creates an ellipse geometry implementation.
         /// </summary>
         /// <param name="rect">The bounds of the ellipse.</param>
-        /// <returns>An ellipse geometry..</returns>
+        /// <returns>An ellipse geometry.</returns>
         IGeometryImpl CreateEllipseGeometry(Rect rect);
 
         /// <summary>
diff --git a/src/Avalonia.Base/Utilities/TypeUtilities.cs b/src/Avalonia.Base/Utilities/TypeUtilities.cs
index 3a82bf02e0..7dbb0872f5 100644
--- a/src/Avalonia.Base/Utilities/TypeUtilities.cs
+++ b/src/Avalonia.Base/Utilities/TypeUtilities.cs
@@ -306,7 +306,7 @@ namespace Avalonia.Utilities
         /// if the value could not be converted.
         /// </summary>
         /// <param name="value">The value to convert.</param>
-        /// <param name="type">The type to convert to..</param>
+        /// <param name="type">The type to convert to.</param>
         /// <param name="culture">The culture to use.</param>
         /// <returns>A value of <paramref name="type"/>.</returns>
         [RequiresUnreferencedCode(TrimmingMessages.TypeConversionRequiresUnreferencedCodeMessage)]
diff --git a/src/Avalonia.Controls/Primitives/PopupPositioning/IPopupPositioner.cs b/src/Avalonia.Controls/Primitives/PopupPositioning/IPopupPositioner.cs
index 0c9bb89caa..4029782772 100644
--- a/src/Avalonia.Controls/Primitives/PopupPositioning/IPopupPositioner.cs
+++ b/src/Avalonia.Controls/Primitives/PopupPositioning/IPopupPositioner.cs
@@ -216,7 +216,7 @@ namespace Avalonia.Controls.Primitives.PopupPositioning
         /// 
         /// If the adjusted position also ends up being constrained, the resulting position of the
         /// FlipX adjustment will be the one before the adjustment.
-        /// /// </remarks>
+        /// </remarks>
         FlipX = 4,
 
         /// <summary>