feat: Adhere to HorizontalOffset and VerticalOffset

src/Uno.UI/Mixins/DependencyPropertyMixins.tt

@@ -90,8 +90,6 @@
 				.Property("Child", "UIElement", "null", frameworkPropertyOption: "ValueInheritsDataContext")
 				.Property("IsLightDismissEnabled", "bool", "false")
 				//.Property("ChildTransitions", "TransitionCollection", "null")
-				.Property("HorizontalOffset", "double", "0")
-				.Property("VerticalOffset", "double", "0")
 
 		.Namespace("Uno.UI.Controls.Legacy")
 			.Class("ListViewBase", condition: "XAMARIN_IOS")

src/Uno.UI/UI/Xaml/Controls/Flyout/FlyoutPopupPanel.cs

@@ -33,6 +33,8 @@ public FlyoutBasePopupPanel(FlyoutBase flyout) : base(flyout._popup)
 		protected override bool FullPlacementRequested => _flyout.EffectivePlacement == FlyoutPlacementMode.Full;
 
 		internal override FlyoutBase Flyout => _flyout;
+
+		protected override int PopupPlacementTargetMargin => 5;
 	}
 }
 #endif

src/Uno.UI/UI/Xaml/Controls/Popup/Popup.Legacy.cs

@@ -90,7 +90,7 @@ private void OnBasePropertyChanged(DependencyObject sender, DependencyProperty d
 			get => GetHorizontalOffsetValue();
 			set => SetHorizontalOffsetValue(value);
 		}
-		private new void OnHorizontalOffsetChanged(double oldValue, double newValue)
+		private void OnHorizontalOffsetChanged(double oldValue, double newValue)
 			=> base.HorizontalOffset = newValue;
 
 		[GeneratedDependencyProperty(DefaultValue = 0.0, LocalCache = false, ChangedCallback = true)]
@@ -104,7 +104,7 @@ private void OnBasePropertyChanged(DependencyObject sender, DependencyProperty d
 			set => SetVerticalOffsetValue(value);
 		}
 
-		private new void OnVerticalOffsetChanged(double oldValue, double newValue)
+		private void OnVerticalOffsetChanged(double oldValue, double newValue)
 			=> base.VerticalOffset = newValue;
 
 		[GeneratedDependencyProperty(DefaultValue = 0.0, LocalCache = false, ChangedCallback = true)]

src/Uno.UI/UI/Xaml/Controls/Popup/Popup.cs

@@ -107,12 +107,6 @@ private void OnPopupPanelChanged(PopupPanel oldHost, PopupPanel newHost)
 
 		partial void OnPopupPanelChangedPartial(PopupPanel previousPanel, PopupPanel newPanel);
 
-		partial void OnVerticalOffsetChangedPartial(double oldVerticalOffset, double newVerticalOffset)
-			=> PopupPanel?.InvalidateMeasure();
-
-		partial void OnHorizontalOffsetChangedPartial(double oldHorizontalOffset, double newHorizontalOffset)
-			=> PopupPanel?.InvalidateMeasure();
-
 		internal override void UpdateThemeBindings(Data.ResourceUpdateReason updateReason)
 		{
 			base.UpdateThemeBindings(updateReason);
@@ -156,7 +150,7 @@ public FrameworkElement PlacementTarget
 				nameof(PlacementTarget),
 				typeof(FrameworkElement),
 				typeof(Popup),
-				new FrameworkPropertyMetadata(default(FrameworkElement)));
+				new FrameworkPropertyMetadata(default(FrameworkElement), FrameworkPropertyMetadataOptions.AffectsArrange));
 
 		/// <summary>
 		/// Gets or sets the preferred placement to be used for the popup, in relation to its placement target.
@@ -175,7 +169,7 @@ public PopupPlacementMode DesiredPlacement
 				nameof(DesiredPlacement),
 				typeof(PopupPlacementMode),
 				typeof(Popup),
-				new FrameworkPropertyMetadata(default(PopupPlacementMode)));
+				new FrameworkPropertyMetadata(default(PopupPlacementMode), FrameworkPropertyMetadataOptions.AffectsArrange));
 
 		/// <summary>
 		/// Gets the actual placement of the popup, in relation to its placement target.
@@ -194,11 +188,49 @@ public PopupPlacementMode ActualPlacement
 			}
 		}
 
+		/// <summary>
+		/// Gets or sets the distance between the left side of the application window and the left side of the popup.
+		/// </summary>
+		public double HorizontalOffset
+		{
+			get => (double)GetValue(HorizontalOffsetProperty);
+			set => SetValue(HorizontalOffsetProperty, value);
+		}
+
+		/// <summary>
+		/// Gets the identifier for the HorizontalOffset dependency property.
+		/// </summary>
+		public static DependencyProperty HorizontalOffsetProperty { get; } =
+			DependencyProperty.Register(
+				nameof(HorizontalOffset),
+				typeof(double),
+				typeof(Popup),
+				new FrameworkPropertyMetadata(0.0, FrameworkPropertyMetadataOptions.AffectsMeasure));
+
+		/// <summary>
+		/// Gets or sets the distance between the top of the application window and the top of the popup.
+		/// </summary>
+		public double VerticalOffset
+		{
+			get => (double)GetValue(VerticalOffsetProperty);
+			set => SetValue(VerticalOffsetProperty, value);
+		}
+
+		/// <summary>
+		/// Gets the identifier for the VerticalOffset dependency property.
+		/// </summary>
+		public static DependencyProperty VerticalOffsetProperty { get; } =
+			DependencyProperty.Register(
+				nameof(VerticalOffset),
+				typeof(double),
+				typeof(Popup),
+				new FrameworkPropertyMetadata(0.0, FrameworkPropertyMetadataOptions.AffectsMeasure));
+
 		/// <summary>
 		/// Raised when the ActualPlacement property changes.
 		/// </summary>
 		public event EventHandler<object> ActualPlacementChanged;
-
+		
 		private void ApplyLightDismissOverlayMode()
 		{
 			if (PopupPanel != null)

src/Uno.UI/UI/Xaml/Controls/Popup/PopupPanel.Placement.cs

@@ -63,8 +63,9 @@ partial class PopupPanel
 	/// <summary>
 	/// This value is an arbitrary value for the placement of
 	/// a popup below its anchor.
+	/// TODO: To be removed in favor of HorizontalOffset and VerticalOffset.
 	/// </summary>
-	protected virtual int PopupPlacementTargetMargin => 5;
+	protected virtual int PopupPlacementTargetMargin => 0;
 
 	private void Window_SizeChanged(object sender, WindowSizeChangedEventArgs e)
 		=> InvalidateMeasure();
@@ -149,23 +150,23 @@ protected virtual Rect CalculatePopupPlacement(Popup popup, Size desiredSize, Si
 			{
 				case FlyoutBase.MajorPlacementMode.Top:
 					finalPosition = new Point(
-						x: anchorRect.Left + halfAnchorWidth - halfChildWidth,
-						y: anchorRect.Top - PopupPlacementTargetMargin - desiredSize.Height);
+						x: anchorRect.Left + halfAnchorWidth - halfChildWidth + popup.HorizontalOffset,
+						y: anchorRect.Top - PopupPlacementTargetMargin - desiredSize.Height + popup.VerticalOffset);
 					break;
 				case FlyoutBase.MajorPlacementMode.Bottom:
 					finalPosition = new Point(
-						x: anchorRect.Left + halfAnchorWidth - halfChildWidth,
-						y: anchorRect.Bottom + PopupPlacementTargetMargin);
+						x: anchorRect.Left + halfAnchorWidth - halfChildWidth + popup.HorizontalOffset,
+						y: anchorRect.Bottom + PopupPlacementTargetMargin + popup.VerticalOffset);
 					break;
 				case FlyoutBase.MajorPlacementMode.Left:
 					finalPosition = new Point(
-						x: anchorRect.Left - PopupPlacementTargetMargin - desiredSize.Width,
-						y: anchorRect.Top + halfAnchorHeight - halfChildHeight);
+						x: anchorRect.Left - PopupPlacementTargetMargin - desiredSize.Width + popup.HorizontalOffset,
+						y: anchorRect.Top + halfAnchorHeight - halfChildHeight + popup.VerticalOffset);
 					break;
 				case FlyoutBase.MajorPlacementMode.Right:
 					finalPosition = new Point(
-						x: anchorRect.Right + PopupPlacementTargetMargin,
-						y: anchorRect.Top + halfAnchorHeight - halfChildHeight);
+						x: anchorRect.Right + PopupPlacementTargetMargin + popup.HorizontalOffset,
+						y: anchorRect.Top + halfAnchorHeight - halfChildHeight + popup.VerticalOffset);
 					break;
 				case FlyoutBase.MajorPlacementMode.Full:
 #if __IOS__ || __ANDROID__

src/Uno.UI/UI/Xaml/Controls/ToolTip/ToolTipPopupPanel.cs

@@ -10,5 +10,7 @@ internal ToolTipPopupPanel(ToolTip toolTip) : base(toolTip.Popup)
 		{
 			Background = null; // No light dismiss for tooltip, dismiss is managed by the cursor location
 		}
+
+		protected override int PopupPlacementTargetMargin => 5;
 	}
 }