Refines MAUI Dialog Layout and Active State Management (#3390)

* check to see if dialog page is attached to window

* fix race condition in dialog service navigation state updates

Ensures that PageNavigationSource and IsActive state updates are deferred until the dialog has been pushed by using ContinueWith on the asynchronous ConfigureLayout call. This prevents state updates from executing before the modal is actually displayed.

* fixed window deactivation state

* fix dialog mask layout and tap gesture reliability

Replaces the root AbsoluteLayout in DialogContainerPage with a Grid. This ensures the background mask fills the screen naturally without needing proportional sizing or explicit WidthRequest/HeightRequest bindings, which were causing tap gestures to fail on some MAUI platforms.

Author: brianlagunas

src/Maui/Prism.Maui/Dialogs/DialogContainerPage.cs

@@ -89,7 +89,12 @@ public virtual async Task DoPop(Page currentPage)
     /// <returns>The content layout for the dialog container page.</returns>
     protected virtual View GetContentLayout(Page currentPage, View dialogView, bool hideOnBackgroundTapped, ICommand dismissCommand, IDialogParameters parameters)
     {
-        var overlay = new AbsoluteLayout();
+        // Use a Grid so the mask fills the page naturally without needing
+        // AbsoluteLayout proportional sizing, which conflicted with the
+        // WidthRequest/HeightRequest bindings and caused tap gestures on
+        // the mask to not fire reliably across MAUI platforms.
+        var overlay = new Grid();
+
         var popupContainer = new DialogContainerView
         {
             IsPopupContent = true,
@@ -118,20 +123,21 @@ protected virtual View GetContentLayout(Page currentPage, View dialogView, bool
                             source: this));
         }
 
-        AbsoluteLayout.SetLayoutFlags(popupContainer, AbsoluteLayoutFlags.PositionProportional);
-        var popupBounds = DialogLayout.GetLayoutBounds(dialogView);
-        AbsoluteLayout.SetLayoutBounds(popupContainer, popupBounds);
-
-        var useMask = DialogLayout.GetUseMask(popupContainer.Content) ?? true;
+        var useMask = DialogLayout.GetUseMask(dialogView) ?? true;
         if (useMask)
         {
             var mask = GetMask(currentPage, dialogView, hideOnBackgroundTapped, dismissCommand);
-            AbsoluteLayout.SetLayoutFlags(mask, AbsoluteLayoutFlags.All);
-            AbsoluteLayout.SetLayoutBounds(mask, new Rect(0, 0, 1, 1));
             overlay.Children.Add(mask);
         }
 
-        overlay.Children.Add(popupContainer);
+        // Keep an AbsoluteLayout for the popup so LayoutBounds positioning still works
+        var popupArea = new AbsoluteLayout();
+        AbsoluteLayout.SetLayoutFlags(popupContainer, AbsoluteLayoutFlags.PositionProportional);
+        var popupBounds = DialogLayout.GetLayoutBounds(dialogView);
+        AbsoluteLayout.SetLayoutBounds(popupContainer, popupBounds);
+        popupArea.Children.Add(popupContainer);
+
+        overlay.Children.Add(popupArea);
         return overlay;
     }
 
@@ -146,29 +152,18 @@ protected virtual View GetContentLayout(Page currentPage, View dialogView, bool
     private View GetMask(Page currentPage, View dialogView, bool hideOnBackgroundTapped, ICommand dismissCommand)
     {
         View mask = DialogLayout.GetMask(dialogView);
-        var reference = currentPage.GetParentWindow().Page;
         if (mask is null)
         {
             Style overlayStyle = GetOverlayStyle(dialogView, currentPage);
 
             mask = new BoxView
             {
                 Style = overlayStyle,
-                //HeightRequest = reference.Height,
-                //WidthRequest = reference.Width
             };
         }
 
-        mask.SetBinding(WidthRequestProperty, new Binding
-        {
-            Path = nameof(Width),
-            Source = reference
-        });
-        mask.SetBinding(HeightRequestProperty, new Binding
-        {
-            Path = nameof(Height),
-            Source = reference
-        });
+        // No explicit WidthRequest/HeightRequest needed — the Grid parent
+        // sizes the mask to fill the page automatically.
 
         if (hideOnBackgroundTapped)
         {

src/Maui/Prism.Maui/Dialogs/DialogServiceBase.cs

@@ -97,12 +97,23 @@ async Task DialogAware_RequestClose(IDialogResult outResult)
 
             var dismissCommand = new DelegateCommand(() => dialogAware.RequestClose.Invoke(), dialogAware.CanCloseDialog);
 
+            // ConfigureLayout is async (it awaits DoPush internally). Since ShowDialog is void,
+            // we use ContinueWith to defer post-push work until the modal is actually displayed.
+            // Without this, NavigationSource resets and IsActive updates race ahead of the push.
             PageNavigationService.NavigationSource = PageNavigationSource.DialogService;
-            dialogModal.ConfigureLayout(currentPage, view, closeOnBackgroundTapped, dismissCommand, parameters);
-            PageNavigationService.NavigationSource = PageNavigationSource.Device;
+            dialogModal.ConfigureLayout(currentPage, view, closeOnBackgroundTapped, dismissCommand, parameters)
+                .ContinueWith(t =>
+                {
+                    if (t.IsFaulted)
+                    {
+                        callback.Invoke(t.Exception?.InnerException ?? t.Exception);
+                        return;
+                    }
 
-            MvvmHelpers.InvokeViewAndViewModelAction<IActiveAware>(currentPage, aa => aa.IsActive = false);
-            MvvmHelpers.InvokeViewAndViewModelAction<IActiveAware>(view, aa => aa.IsActive = true);
+                    PageNavigationService.NavigationSource = PageNavigationSource.Device;
+                    MvvmHelpers.InvokeViewAndViewModelAction<IActiveAware>(currentPage, aa => aa.IsActive = false);
+                    MvvmHelpers.InvokeViewAndViewModelAction<IActiveAware>(view, aa => aa.IsActive = true);
+                }, TaskScheduler.FromCurrentSynchronizationContext());
         }
         catch (Exception ex)
         {

src/Maui/Prism.Maui/Navigation/PrismWindow.cs

@@ -105,7 +105,7 @@ protected override void OnActivated()
         protected override void OnDeactivated()
         {
             IsActive = false;
-            MvvmHelpers.InvokeViewAndViewModelAction<IActiveAware>(CurrentPage, x => x.IsActive = true);
+            MvvmHelpers.InvokeViewAndViewModelAction<IActiveAware>(CurrentPage, x => x.IsActive = false);
         }
 
         /// <summary>