Resolved the Popup Position and Size issue.

maui/src/Popup/Helpers/PopupExtension/PopupExtension.Android.cs

@@ -120,12 +120,12 @@ internal static int GetLocationInApp(VisualElement virtualView)
 					{
 						int[] decorCoordinates = new int[2] { 0, 0 };
 						decorView.GetLocationInWindow(decorCoordinates);
-						return (int)Math.Round((viewCoordinates[1] - decorCoordinates[1]) / WindowOverlayHelper._density);
+						return Math.Max((int)Math.Round((viewCoordinates[1] - decorCoordinates[1]) / WindowOverlayHelper._density), 0);
 					}
 				}
 				else
 				{
-					return (int)Math.Round((viewCoordinates[1] - GetWindowInsets("Top")) / WindowOverlayHelper._density);
+					return Math.Max((int)Math.Round((viewCoordinates[1] - GetWindowInsets("Top")) / WindowOverlayHelper._density), 0);
 				}
 			}
 
@@ -148,7 +148,12 @@ internal static int GetScreenWidth()
 				return widthPixel;
 			}
 
-			return (int)Math.Round(platformRootView!.Width / WindowOverlayHelper._density);
+			int leftInsets = 0;
+#if NET10_0
+            // In .NET 10, the root view’s width in landscape includes the navigation bar, so subtract the left window inset from the root view width to get the usable content width.
+            leftInsets = PopupExtension.GetWindowInsets("Left");
+#endif
+			return (int)Math.Round((platformRootView!.Width - leftInsets) / WindowOverlayHelper._density);
 		}
 
 		/// <summary>
@@ -169,13 +174,24 @@ internal static int GetScreenHeight()
 			}
 			else if (platformRootView is not null)
 			{
+				int topInsets = 0;
+				int bottomInsets = 0;
+#if NET10_0
+                // In .NET 10, the root view’s height includes the navigation bar, so subtract the bottom window inset from the root view height to get the usable content height.
+                bottomInsets = PopupExtension.GetWindowInsets("Bottom");
+                if (!WindowFlagHasFullScreen)
+                {
+                    topInsets = PopupExtension.GetWindowInsets("Top");
+                }
+#endif
+
 				if (IsResizeMode() && !WindowFlagHasNoLimits)
 				{
 					platformRootViewHeight = platformRootView.Height + (GetKeyboardHeight() * WindowOverlayHelper._density);
 				}
 				else
 				{
-					platformRootViewHeight = platformRootView.Height;
+					platformRootViewHeight = platformRootView.Height - topInsets - bottomInsets;
 				}
 
 				return (int)Math.Round(platformRootViewHeight / WindowOverlayHelper._density);
@@ -239,15 +255,30 @@ internal static int GetWindowInsets(string position)
 				var windowInsets = ViewCompat.GetRootWindowInsets(WindowOverlayHelper._decorViewContent);
 				if (windowInsets is not null)
 				{
+#pragma warning disable CS8602 // Dereference of a possibly null reference.
 					var insets = windowInsets.GetInsets(WindowInsetsCompat.Type.SystemBars());
 					switch (position)
 					{
 						case "Bottom":
 							return insets.Bottom;
 						case "Top":
-							return insets.Top;
+							{
+#if NET10_0
+                            // In .NET 10 case, fall back to decorViewFrame when Top inset is 0.
+                            return insets.Top == 0 ? (int)Math.Round((WindowOverlayHelper._decorViewFrame?.Top ?? 0f) / WindowOverlayHelper._density) : insets.Top;
+#else
+								return insets.Top;
+#endif
+							}
 						case "Left":
-							return insets.Left;
+							{
+#if NET10_0
+                            // In .NET 10 case, fall back to decorViewFrame when Left inset is 0.
+                            return insets.Left == 0 ? (int)Math.Round((WindowOverlayHelper._decorViewFrame?.Left ?? 0f) / WindowOverlayHelper._density) : insets.Left;
+#else
+								return insets.Left;
+#endif
+							}
 						case "Right":
 							return insets.Right;
 						case "Keyboard":
@@ -259,6 +290,8 @@ internal static int GetWindowInsets(string position)
 						default:
 							return 0;
 					}
+#pragma warning restore CS8602
+
 				}
 			}
 

maui/src/Popup/Helpers/PopupExtension/PopupExtension.iOS.cs

@@ -120,10 +120,28 @@ internal static int GetActionBarHeight()
 		internal static int GetSafeAreaHeight(string position)
 		{
 			// The popup is drawn within the safe area when shown relative to a view. Safe area calculations apply only to the iOS X simulator on iOS.
+#pragma warning disable CS0618 // Suppressing CS0618 warning because Page.GetUseSafeArea is marked obsolete in .NET 10.
 			if (Microsoft.Maui.Controls.PlatformConfiguration.iOSSpecific.Page.GetUseSafeArea(GetMainPage()))
+#pragma warning restore CS0618
 			{
 				var platformWindow = WindowOverlayHelper._window?.ToPlatform() as UIWindow;
-				var statusBarOrientation = platformWindow?.WindowScene?.InterfaceOrientation;
+				UIInterfaceOrientation? statusBarOrientation = null;
+				var scene = platformWindow?.WindowScene;
+				if (scene != null)
+				{
+#if IOS || MACCATALYST
+					if (OperatingSystem.IsIOSVersionAtLeast(16, 0) || OperatingSystem.IsMacCatalystVersionAtLeast(16, 0))
+					{
+						statusBarOrientation = scene.EffectiveGeometry.InterfaceOrientation;
+					}
+					else
+					{
+#pragma warning disable CA1422 // InterfaceOrientation is obsoleted on newer SDKs; guarded by OS version checks
+						statusBarOrientation = scene.InterfaceOrientation;
+#pragma warning restore CA1422
+					}
+#endif
+				}
 
 				// Since StatusBarHeight is already calculated, the top safe area does not need to be computed.
 				if (position == "Top")

maui/src/Popup/PopupFooter.cs

@@ -83,7 +83,9 @@ public PopupFooter(PopupView popupView)
 		{
 #if IOS
 			// The value for the IgnoreSafeArea property is being set by retrieving the safe area value from the main page.
+#pragma warning disable CS0618 // Suppressing CS0618 warning because Page.GetUseSafeArea is marked obsolete in .NET 10.
 			IgnoreSafeArea = !Microsoft.Maui.Controls.PlatformConfiguration.iOSSpecific.Page.GetUseSafeArea(PopupExtension.GetMainPage());
+#pragma warning restore CS0618
 #endif
 			_popupView = popupView;
 			Initialize();
@@ -194,7 +196,9 @@ void AddChildViews()
 			if (footerView is not null)
 			{
 				// The value for the IgnoreSafeArea property is being set by retrieving the safe area value from the main page.
+#pragma warning disable CS0618 // Suppressing CS0618 warning because Layout.IgnoreSafeArea is marked obsolete in .NET 10.
 				footerView.IgnoreSafeArea = IgnoreSafeArea;
+#pragma warning restore CS0618
 				if (_popupView._popup.FooterTemplate is null)
 				{
 					if (_popupView._popup.AppearanceMode == PopupButtonAppearanceMode.OneButton)

maui/src/Popup/PopupHeader.cs

@@ -68,7 +68,9 @@ public PopupHeader(PopupView popup)
 		{
 #if IOS
 			// When Page SafeArea is false, close icon overlaps header,because HeaderView arranging with safeArea.
+#pragma warning disable CS0618 // Suppressing CS0618 warning because Page.GetUseSafeArea is marked obsolete in .NET 10.
 			IgnoreSafeArea = !Microsoft.Maui.Controls.PlatformConfiguration.iOSSpecific.Page.GetUseSafeArea(PopupExtension.GetMainPage());
+#pragma warning restore CS0618
 #endif
 			_popupView = popup;
 			Initialize();
@@ -149,7 +151,9 @@ void AddChildViews()
 				if (headerView is not null)
 				{
 					// The value for the IgnoreSafeArea property is being set by retrieving the safe area value from the main page.
+#pragma warning disable CS0618 // Suppressing CS0618 warning because Layout.IgnoreSafeArea is marked obsolete in .NET 10.
 					headerView.IgnoreSafeArea = IgnoreSafeArea;
+#pragma warning restore CS0618
 					bool isFullScreen = _popupView._popup.CanShowPopupInFullScreen;
 					if (isFullScreen)
 					{

maui/src/Popup/PopupMessageView.cs

@@ -60,7 +60,9 @@ public PopupMessageView(PopupView popupView)
 		{
 #if IOS
 			// The value for the IgnoreSafeArea property is being set by retrieving the safe area value from the main page.
+#pragma warning disable CS0618 // Suppressing CS0618 warning because Page.GetUseSafeArea is marked obsolete in .NET 10.
 			IgnoreSafeArea = !Microsoft.Maui.Controls.PlatformConfiguration.iOSSpecific.Page.GetUseSafeArea(PopupExtension.GetMainPage());
+#pragma warning restore CS0618
 #endif
 			_popupView = popupView;
 			Initialize();

maui/src/Popup/SfPopup/SfPopup.Windows.cs

@@ -228,9 +228,8 @@ async void OnPlatformWindowSizeChanged(object sender, WindowSizeChangedEventArgs
 					// Abort the PopupView animation when the window size changes.
 					AbortPopupViewAnimation();
 					ResetAnimatedProperties();
-					ResetPopupWidthHeight();
-
 					SyncPopupDimensionFields();
+					ResetPopupWidthHeight();
 
 					// Need to update the effect visual size, when the window is resized or the orientation changes.
 					if (IsOpen && ShowOverlayAlways && OverlayMode is PopupOverlayMode.Blur)

maui/src/Popup/SfPopup/SfPopup.cs

@@ -347,7 +347,7 @@ public partial class SfPopup : SfView, IParentThemeElement
 		/// <summary>
         /// Identifies the Padding bindable property.
         /// </summary>
-        public static readonly BindableProperty PaddingProperty =
+        public static new readonly BindableProperty PaddingProperty =
             BindableProperty.Create("Padding", typeof(Thickness), typeof(SfPopup), new Thickness(0.0), BindingMode.Default, propertyChanged: OnPaddingPropertyChanged);
 
 		/// <summary>
@@ -1734,7 +1734,8 @@ public void ShowRelativeToView(View relativeView, PopupRelativePosition relative
 		/// </example>
 		public void Dismiss()
 		{
-			if (IsOpen && !StaysOpen)
+			// Maui:990257 When Dismiss() is called, the popup should close regardless of whether the StaysOpen property is set to true.
+			if (IsOpen)
 			{
 				OpenOrClosePopup(false);
 			}
@@ -2102,8 +2103,12 @@ void RaisePopupEvent()
 		/// </summary>
 		void DisplayPopup()
 		{
-			if (_popupView is null)
+			// 989436 : [Android] Popup is not shown when IsOpen is set in XAML or constructor at loading with a Shell page.
+			// In Android, the Shell page is not loaded initially, so the popup is displayed only after the Shell page has loaded.
+			if (_popupView == null || (PopupExtension.GetMainWindowPage() is Shell shellPage && !shellPage.IsLoaded))
 			{
+				_isOpenDeferred = true;
+				WireEvents();
 				return;
 			}
 #if ANDROID
@@ -2775,8 +2780,13 @@ void WireEvents()
 				if (windowPage.Navigation.ModalStack.LastOrDefault() is not null)
 				{
 					// LayoutChanged only wired for Modal page. Since when Popup is opened OnAppearing of Modal page height and width is not update in native level.
-					page.LayoutChanged -= OnPageLayoutChanged;
-					page.LayoutChanged += OnPageLayoutChanged;
+#if NET10_0
+					page.SizeChanged -= this.OnPageSizeChanged;
+					page.SizeChanged += this.OnPageSizeChanged;
+#else
+					page.SizeChanged -= this.OnPageLayoutChanged;
+					page.SizeChanged += this.OnPageLayoutChanged;
+#endif
 				}
 #else
 				// while calling show() from onAppearing, page.window is not null. So fails the first condition and hook the onMainPageLoaded.
@@ -2836,6 +2846,23 @@ void OnApplicationPageAppearing(object? sender, Page e)
 			WireEvents();
 		}
 
+		/// <summary>
+		/// Raise when the current page size has changed.
+		/// </summary>
+		/// <param name="sender">Represents current Page.</param>
+		/// <param name="e">Corresponding property changed event args.</param>
+		private void OnPageSizeChanged(object? sender, EventArgs e)
+		{
+			this.InitializeOverlay();
+			this.CheckAndOpenDeferredPopup();
+
+			// Here need to unwire the LayoutChanged. If not, this will cause issue when resizing the windows with Popup.IsOpen false.
+			if (sender is Page page)
+			{
+				page.SizeChanged -= this.OnPageSizeChanged;
+			}
+		}
+
 		/// <summary>
 		/// Raise when the current page layout has changed.
 		/// </summary>
@@ -2849,7 +2876,11 @@ void OnPageLayoutChanged(object? sender, EventArgs e)
 			// Unwire the LayoutChanged to avoid issues when resizing the window with Popup.IsOpen set to false.
 			if (sender is Page page)
 			{
-				page.LayoutChanged -= OnPageLayoutChanged;
+#if NET10_0
+				page.SizeChanged -= this.OnPageSizeChanged;
+#else
+				page.LayoutChanged -= this.OnPageLayoutChanged;
+#endif
 			}
 		}
 
@@ -3485,12 +3516,19 @@ protected override void OnHandlerChanged()
 			if (Handler is null && _popupOverlay is not null)
 			{
 				_popupOverlay.Dispose();
+				_popupOverlay = null;
 			}
 
 			if (!_isOverlayAdded && Handler != null)
             {
 				InitializeOverlay();
-            }
+
+				// 989436: Popup is not shown when IsOpen is set in XAML or in the constructor during loading with a direct page. So, the popup needs to be displayed when it is still not shown from OnIsOpenChanged.
+				if (_isOverlayAdded)
+				{
+					CheckAndOpenDeferredPopup();
+				}
+			}
 
 			base.OnHandlerChanged();
 		}
@@ -3771,6 +3809,10 @@ static void OnShowHeaderPropertyChanged(BindableObject bindable, object oldValue
 							if (popup._popupView.Contains(popup._popupView._headerView))
 							{
 								popup._popupView.Remove(popup._popupView._headerView);
+								if (popup._popupView._headerView.Handler is not null)
+								{
+									popup._popupView._headerView.Handler.DisconnectHandler();
+								}
 							}
 						}
 					}

maui/src/Popup/SfPopup/SfPopup.iOS.cs

@@ -58,11 +58,16 @@ internal void WirePlatformSpecificEvents()
 				if (ModalPage is not null)
 				{
 					// Wired the size change event for the Modal page when a popup is opened from it.
-					ModalPage.SizeChanged += OnMainPageSizeChanged;
+					ModalPage.SizeChanged += this.OnMainPageSizeChanged;
+				}
+				else if (windowPage is Shell shellPage && shellPage.CurrentPage != null)
+				{
+					// Maui:990575-TODO : Shell page size changed event not triggered after .NET 10 update, so wire the size changed event for the current page of the Shell page.
+					shellPage.CurrentPage.SizeChanged += this.OnMainPageSizeChanged;
 				}
 				else
 				{
-					windowPage.SizeChanged += OnMainPageSizeChanged;
+					windowPage.SizeChanged += this.OnMainPageSizeChanged;
 				}
 			}
 
@@ -82,6 +87,11 @@ internal void UnWirePlatformSpecificEvents()
 					// Wired the size change event for the Modal page when a popup is opened from it.
 					ModalPage.SizeChanged -= OnMainPageSizeChanged;
 				}
+				else if (windowPage is Shell shellPage && shellPage.CurrentPage != null)
+				{
+					// Maui:990575-TODO : Shell page size changed event not triggered after .NET 10 update, so unwire the size changed event for the current page of the Shell page.
+					shellPage.CurrentPage.SizeChanged -= this.OnMainPageSizeChanged;
+				}
 				else
 				{
 					windowPage.SizeChanged -= OnMainPageSizeChanged;

maui/tests/Syncfusion.Maui.Toolkit.UnitTest/Layout/SfPopupUnitTest.cs

@@ -688,7 +688,7 @@ public void TestSfPopupShow(bool value)
 		}
 		[Theory]
 		[InlineData(false, false, false)]
-		[InlineData(true, true, true)]
+		[InlineData(true, true, false)]
 		[InlineData(false, true, false)]
 		public void TestSfPopupDismiss(bool isOpen, bool staysOpen, bool Open)
 		{