DiagnosticView Ordering

build/PackageDiffIgnore.xml

@@ -1982,6 +1982,10 @@
 			<Member fullName="System.Threading.Tasks.Task`1&lt;System.Boolean&gt; Uno.UI.Helpers.TypeMappings.WaitForResume()" reason="Not really considered a public API, used by internal tooling" />
 			<Member fullName="System.Void Uno.UI.Helpers.TypeMappings.Resume(System.Boolean updateLayout)" reason="Not really considered a public API, used by internal tooling" />
 			<!-- END TypeMappings -->
+
+			<!-- BEGIN DiagnosticsOverlay -->
+			<Member fullName="System.Void Uno.Diagnostics.UI.DiagnosticsOverlay.Add(System.String id, System.String name, Microsoft.UI.Xaml.UIElement preview, System.Func`1&lt;Microsoft.UI.Xaml.UIElement&gt; details)" reason="Recently public, nobody uses it yet." />
+			<!-- END DiagnosticsOverlay -->
 		</Methods>
 	</IgnoreSet>
 

src/Uno.Foundation/Diagnostics/DiagnosticViewRegistry.cs

@@ -12,7 +12,7 @@ internal static class DiagnosticViewRegistry
 {
 	internal static EventHandler<IImmutableList<DiagnosticViewRegistration>>? Added;
 
-	private static ImmutableArray<DiagnosticViewRegistration> _registrations = ImmutableArray<DiagnosticViewRegistration>.Empty;
+	private static ImmutableArray<DiagnosticViewRegistration> _registrations = [];
 
 	/// <summary>
 	/// Gets the list of registered diagnostic providers.
@@ -35,15 +35,17 @@ public static void Register(IDiagnosticView view, DiagnosticViewRegistrationMode
 	}
 }
 
-internal record DiagnosticViewRegistration(DiagnosticViewRegistrationMode Mode, IDiagnosticView View);
+internal sealed record DiagnosticViewRegistration(
+	DiagnosticViewRegistrationMode Mode,
+	IDiagnosticView View);
 
 public enum DiagnosticViewRegistrationMode
 {
 	/// <summary>
 	/// Diagnostic is being display on at least one window.
 	/// I.e. only the main/first opened but move to the next one if the current window is closed.
 	/// </summary>
-	One,
+	One, // Default
 
 	/// <summary>
 	/// Diagnostic is being rendered as overlay on each window.
@@ -55,3 +57,18 @@ public enum DiagnosticViewRegistrationMode
 	/// </summary>
 	OnDemand
 }
+
+public enum DiagnosticViewRegistrationPosition
+{
+	Normal = 0, // Default
+
+	/// <summary>
+	/// Register as the first diagnostic view, ensuring it is displayed first.
+	/// </summary>
+	First = -1,
+
+	/// <summary>
+	/// Register as the last diagnostic view, ensuring it is displayed last.
+	///	</summary>
+	Last = 1,
+}

src/Uno.Foundation/Diagnostics/IDiagnosticView.cs

@@ -21,6 +21,8 @@ public interface IDiagnosticView
 	/// </summary>
 	string Name { get; }
 
+	DiagnosticViewRegistrationPosition Position => DiagnosticViewRegistrationPosition.Normal;
+
 	/// <summary>
 	/// Gets a visual element of the diagnostic, usually a value or an icon.
 	/// </summary>

src/Uno.UI.RemoteControl/RemoteControlClient.cs

@@ -33,7 +33,63 @@ public partial class RemoteControlClient : IRemoteControlClient
 	public delegate void RemoteControlClientEventEventHandler(object sender, ClientEventEventArgs args);
 	public delegate void SendMessageFailedEventHandler(object sender, SendMessageFailedEventArgs args);
 
-	public static RemoteControlClient? Instance { get; private set; }
+	public static RemoteControlClient? Instance
+	{
+		get => _instance;
+		private set
+		{
+			_instance = value;
+
+			if (value is { })
+			{
+				while (Interlocked.Exchange(ref _waitingList, null) is { } waitingList)
+				{
+					foreach (var action in waitingList)
+					{
+						action(value);
+					}
+				}
+			}
+		}
+	}
+
+	private static IReadOnlyCollection<Action<RemoteControlClient>>? _waitingList;
+
+	/// <summary>
+	/// Add a callback to be called when the Instance is available.
+	/// </summary>
+	/// <remarks>
+	/// Will be called synchronously if the instance is already available, no need to check for it before.
+	/// </remarks>
+	public static void OnRemoteControlClientAvailable(Action<RemoteControlClient> action)
+	{
+		if (Instance is { })
+		{
+			action(Instance);
+		}
+		else
+		{
+			// Thread-safe way to add the action to a waiting list for the client to be available
+			while (true)
+			{
+				var waitingList = _waitingList;
+				IReadOnlyCollection<Action<RemoteControlClient>> newList = waitingList is null
+					? [action]
+					: [.. waitingList, action];
+
+				if (Instance is { } i) // Last chance to avoid the waiting list
+				{
+					action(i);
+					break;
+				}
+
+				if (ReferenceEquals(Interlocked.CompareExchange(ref _waitingList, newList, waitingList), waitingList))
+				{
+					break;
+				}
+			}
+		}
+	}
 
 	public static RemoteControlClient Initialize(Type appType)
 		=> Instance = new RemoteControlClient(appType);
@@ -59,6 +115,7 @@ internal static RemoteControlClient Initialize(Type appType, ServerEndpointAttri
 
 	private readonly StatusSink _status;
 	private static readonly TimeSpan _keepAliveInterval = TimeSpan.FromSeconds(30);
+	private static RemoteControlClient? _instance;
 	private readonly (string endpoint, int port)[]? _serverAddresses;
 	private readonly Dictionary<string, IClientProcessor> _processors = new();
 	private readonly List<IRemoteControlPreProcessor> _preprocessors = new();
@@ -223,7 +280,6 @@ public void RegisterPreProcessor(IRemoteControlPreProcessor preprocessor)
 
 			_status.Report(ConnectionState.Connecting);
 
-
 			const string lastEndpointKey = "__UNO__" + nameof(RemoteControlClient) + "__last_endpoint";
 			var preferred = ApplicationData.Current.LocalSettings.Values.TryGetValue(lastEndpointKey, out var lastValue) && lastValue is string lastEp
 				? _serverAddresses.FirstOrDefault(srv => srv.endpoint.Equals(lastEp, StringComparison.OrdinalIgnoreCase)).endpoint
@@ -429,7 +485,8 @@ private async Task<Connection> Connect(Uri serverUri, int delay, CancellationTok
 		{
 			if (this.Log().IsEnabled(LogLevel.Trace))
 			{
-				this.Log().Trace($"Connecting to [{serverUri}] failed: {e.Message}");
+				var innerMessage = e.InnerException is { } ie ? $" ({ie.Message})" : "";
+				this.Log().Trace($"Connecting to [{serverUri}] failed: {e.Message}{innerMessage}");
 			}
 
 			return new(this, serverUri, watch, null);

src/Uno.UI.RemoteControl/RemoteControlStatus.cs

@@ -12,8 +12,27 @@ public record RemoteControlStatus(
 	ImmutableHashSet<RemoteControlStatus.MissingProcessor> MissingRequiredProcessors,
 	(long Count, ImmutableHashSet<Type> Types) InvalidFrames)
 {
-	public bool IsAllGood => State == ConnectionState.Connected && IsVersionValid == true && MissingRequiredProcessors.IsEmpty && KeepAlive.State == KeepAliveState.Ok && InvalidFrames.Count == 0;
 
+	/// <summary>
+	/// A boolean indicating if everything is fine with the connection and the handshaking succeeded.
+	/// </summary>
+	public bool IsAllGood =>
+		State == ConnectionState.Connected
+#if !DEBUG
+		// For debug builds, it's annoying to have the version mismatch preventing the connection
+		// Only Uno devs should get this issue, let's not block them.
+		&& IsVersionValid == true
+#endif
+		&& MissingRequiredProcessors.IsEmpty
+		&& KeepAlive.State == KeepAliveState.Ok
+		&& InvalidFrames.Count == 0;
+
+	/// <summary>
+	/// If the connection is problematic, meaning that the connection is not in a good state.
+	/// </summary>
+	/// <remarks>
+	/// It's just a negation of <see cref="IsAllGood"/>.
+	/// </remarks>
 	public bool IsProblematic => !IsAllGood;
 
 	public (Classification kind, string message) GetSummary()

src/Uno.UI.Toolkit/Diagnostics/DiagnosticsOverlay.cs

@@ -2,6 +2,7 @@
 #if WINUI || HAS_UNO_WINUI
 using System;
 using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.Diagnostics;
 using System.Linq;
 using System.Runtime.CompilerServices;
@@ -316,8 +317,8 @@ public void Show(string viewId)
 	/// Add a UI diagnostic element to this overlay.
 	/// </summary>
 	/// <remarks>This will also make this overlay visible (cf. <see cref="Show(bool?)"/>).</remarks>
-	public void Add(string id, string name, UIElement preview, Func<UIElement>? details = null)
-		=> Add(new DiagnosticView(id, name, _ => preview, (_, ct) => new(details?.Invoke())));
+	public void Add(string id, string name, UIElement preview, Func<UIElement>? details = null, DiagnosticViewRegistrationPosition position = default)
+		=> Add(new DiagnosticView(id, name, _ => preview, (_, ct) => new(details?.Invoke()), position));
 
 	/// <summary>
 	/// Add a UI diagnostic element to this overlay.
@@ -464,8 +465,8 @@ private void EnqueueUpdate(bool forceUpdate = false)
 					.Where(ShouldMaterialize)
 					.Select(reg => reg.View)
 					.Concat(_localRegistrations)
-					.Distinct()
-					.ToList();
+					.OrderBy(r => (int)r.Position)
+					.Distinct();
 
 				foreach (var view in viewsThatShouldBeMaterialized)
 				{

src/Uno.UI/Diagnostics/DiagnosticView.Factories.cs

@@ -21,11 +21,16 @@ partial class DiagnosticView
 	/// </remarks>
 	/// <typeparam name="TView">Type of the control.</typeparam>
 	/// <param name="friendlyName">The user-friendly name of the diagnostics view.</param>
-	public static DiagnosticView<TView> Register<TView>(string friendlyName)
+	/// <param name="mode">Defines when the registered diagnostic view should be displayed.</param>
+	/// <param name="position">Defines where the item should be placed in the overlay.</param>
+	public static DiagnosticView<TView> Register<TView>(
+		string friendlyName,
+		DiagnosticViewRegistrationMode mode = default,
+		DiagnosticViewRegistrationPosition position = default)
 		where TView : UIElement, new()
 	{
-		var provider = new DiagnosticView<TView>(typeof(TView).Name, friendlyName, () => new TView());
-		DiagnosticViewRegistry.Register(provider);
+		var provider = new DiagnosticView<TView>(typeof(TView).Name, friendlyName, () => new TView(), position: position);
+		DiagnosticViewRegistry.Register(provider, mode);
 		return provider;
 	}
 
@@ -43,10 +48,15 @@ public static DiagnosticView<TView> Register<TView>(string friendlyName)
 	/// <param name="friendlyName">The user-friendly name of the diagnostics view.</param>
 	/// <param name="factory">Factory to create an instance of the control.</param>
 	/// <param name="mode">Defines when the registered diagnostic view should be displayed.</param>
-	public static DiagnosticView<TView> Register<TView>(string friendlyName, Func<TView> factory, DiagnosticViewRegistrationMode mode = default)
+	/// <param name="position">Defines where the item should be placed in the overlay.</param>
+	public static DiagnosticView<TView> Register<TView>(
+		string friendlyName,
+		Func<TView> factory,
+		DiagnosticViewRegistrationMode mode = default,
+		DiagnosticViewRegistrationPosition position = default)
 		where TView : UIElement
 	{
-		var provider = new DiagnosticView<TView>(typeof(TView).Name, friendlyName, factory);
+		var provider = new DiagnosticView<TView>(typeof(TView).Name, friendlyName, factory, position: position);
 		DiagnosticViewRegistry.Register(provider, mode);
 		return provider;
 	}
@@ -62,17 +72,21 @@ public static DiagnosticView<TView> Register<TView>(string friendlyName, Func<TV
 	/// <param name="friendlyName">The user-friendly name of the diagnostics view.</param>
 	/// <param name="update">Delegate to use to update the <typeparamref name="TView"/> when the <typeparamref name="TState"/> is being updated.</param>
 	/// <param name="details">Optional delegate used to show more details about the diagnostic info when user taps on the view.</param>
+	/// <param name="mode">Defines when the registered diagnostic view should be displayed.</param>
+	/// <param name="position">Defines where the item should be placed in the overlay.</param>
 	/// <returns>A diagnostic view helper class which can be used to push updates of the state (cf. <see cref="DiagnosticView{TView,TState}.Update"/>).</returns>
 	public static DiagnosticView<TView, TState> Register<TView, TState>(
 		string friendlyName,
 		Action<TView, TState> update,
-		Func<TState, object?>? details = null)
+		Func<TState, object?>? details = null,
+		DiagnosticViewRegistrationMode mode = default,
+		DiagnosticViewRegistrationPosition position = default)
 		where TView : FrameworkElement, new()
 	{
 		var provider = details is null
-			? new DiagnosticView<TView, TState>(typeof(TView).Name, friendlyName, _ => new TView(), update)
-			: new DiagnosticView<TView, TState>(typeof(TView).Name, friendlyName, _ => new TView(), update, (ctx, state, ct) => new(details(state)));
-		DiagnosticViewRegistry.Register(provider);
+			? new DiagnosticView<TView, TState>(typeof(TView).Name, friendlyName, _ => new TView(), update, position: position)
+			: new DiagnosticView<TView, TState>(typeof(TView).Name, friendlyName, _ => new TView(), update, (ctx, state, ct) => new(details(state)), position: position);
+		DiagnosticViewRegistry.Register(provider, mode);
 		return provider;
 	}
 
@@ -88,18 +102,22 @@ public static DiagnosticView<TView, TState> Register<TView, TState>(
 	/// <param name="factory">Factory to create an instance of the generic element.</param>
 	/// <param name="update">Delegate to use to update the <typeparamref name="TView"/> when the <typeparamref name="TState"/> is being updated.</param>
 	/// <param name="details">Optional delegate used to show more details about the diagnostic info when user taps on the view.</param>
+	/// <param name="mode">Defines when the registered diagnostic view should be displayed.</param>
+	/// <param name="position">Defines where the item should be placed in the overlay.</param>
 	/// <returns>A diagnostic view helper class which can be used to push updates of the state (cf. <see cref="DiagnosticView{TView,TState}.Update"/>).</returns>
 	public static DiagnosticView<TView, TState> Register<TView, TState>(
 		string friendlyName,
 		Func<IDiagnosticViewContext, TView> factory,
 		Action<TView, TState> update,
-		Func<TState, object?>? details = null)
+		Func<TState, object?>? details = null,
+		DiagnosticViewRegistrationMode mode = default,
+		DiagnosticViewRegistrationPosition position = default)
 		where TView : FrameworkElement
 	{
 		var provider = details is null
-			? new DiagnosticView<TView, TState>(typeof(TView).Name, friendlyName, factory, update)
-			: new DiagnosticView<TView, TState>(typeof(TView).Name, friendlyName, factory, update, (ctx, state, ct) => new(details(state)));
-		DiagnosticViewRegistry.Register(provider);
+			? new DiagnosticView<TView, TState>(typeof(TView).Name, friendlyName, factory, update, position: position)
+			: new DiagnosticView<TView, TState>(typeof(TView).Name, friendlyName, factory, update, (ctx, state, ct) => new(details(state)), position: position);
+		DiagnosticViewRegistry.Register(provider, mode);
 		return provider;
 	}
 }

src/Uno.UI/Diagnostics/DiagnosticView.TView.TState.cs

@@ -15,7 +15,8 @@ public class DiagnosticView<TView, TState>(
 	string name,
 	Func<IDiagnosticViewContext, TView> factory,
 	Action<TView, TState> update,
-	Func<IDiagnosticViewContext, TState, CancellationToken, ValueTask<object?>>? details = null)
+	Func<IDiagnosticViewContext, TState, CancellationToken, ValueTask<object?>>? details = null,
+	DiagnosticViewRegistrationPosition position = default)
 	: IDiagnosticView
 	where TView : FrameworkElement
 {
@@ -37,6 +38,8 @@ public void Update(TState status)
 	/// <inheritdoc />
 	string IDiagnosticView.Name => name;
 
+	DiagnosticViewRegistrationPosition IDiagnosticView.Position => position;
+
 	/// <inheritdoc />
 	object IDiagnosticView.GetElement(IDiagnosticViewContext context)
 		=> _elementsManager.GetView(context);

src/Uno.UI/Diagnostics/DiagnosticView.TView.cs

@@ -14,16 +14,18 @@ public class DiagnosticView<TView>(
 	string id,
 	string name,
 	Func<IDiagnosticViewContext, TView> factory,
-	Func<IDiagnosticViewContext, CancellationToken, ValueTask<object?>>? details = null)
+	Func<IDiagnosticViewContext, CancellationToken, ValueTask<object?>>? details = null,
+	DiagnosticViewRegistrationPosition position = default)
 	: IDiagnosticView
 	where TView : UIElement
 {
 	public DiagnosticView(
 		string id,
 		string name,
 		Func<TView> preview,
-		Func<CancellationToken, ValueTask<object?>>? details = null)
-		: this(id, name, _ => preview(), async (_, ct) => details is null ? null : await details(ct))
+		Func<CancellationToken, ValueTask<object?>>? details = null,
+		DiagnosticViewRegistrationPosition position = default)
+		: this(id, name, _ => preview(), async (_, ct) => details is null ? null : await details(ct), position)
 	{
 	}
 
@@ -33,6 +35,8 @@ public DiagnosticView(
 	/// <inheritdoc />
 	string IDiagnosticView.Name => name;
 
+	DiagnosticViewRegistrationPosition IDiagnosticView.Position => position;
+
 	/// <inheritdoc />
 	object IDiagnosticView.GetElement(IDiagnosticViewContext context) => factory(context);
 

src/Uno.UI/Diagnostics/DiagnosticView.cs

@@ -14,15 +14,17 @@ public partial class DiagnosticView(
 	string id,
 	string name,
 	Func<IDiagnosticViewContext, UIElement> factory,
-	Func<IDiagnosticViewContext, CancellationToken, ValueTask<object?>>? details = null)
-	: DiagnosticView<UIElement>(id, name, factory, details)
+	Func<IDiagnosticViewContext, CancellationToken, ValueTask<object?>>? details = null,
+	DiagnosticViewRegistrationPosition position = default)
+	: DiagnosticView<UIElement>(id, name, factory, details, position)
 {
 	public DiagnosticView(
 		string id,
 		string name,
 		Func<UIElement> preview,
-		Func<CancellationToken, ValueTask<object?>>? details = null)
-		: this(id, name, _ => preview(), async (_, ct) => details is null ? null : await details(ct))
+		Func<CancellationToken, ValueTask<object?>>? details = null,
+		DiagnosticViewRegistrationPosition position = default)
+		: this(id, name, _ => preview(), async (_, ct) => details is null ? null : await details(ct), position)
 	{
 	}
 }

src/Uno.UI/Diagnostics/DiagnosticViewManager.TView.TState.cs

@@ -12,7 +12,9 @@ namespace Uno.Diagnostics.UI;
 /// <typeparam name="TState">Type of the state used to update the <typeparamref name="TView"/>.</typeparam>
 /// <param name="factory">Factory to create an instance of the <typeparamref name="TView"/>.</param>
 /// <param name="update">Delegate to use to update the <typeparamref name="TView"/> on <see cref="NotifyChanged"/>.</param>
-internal class DiagnosticViewManager<TView, TState>(Func<IDiagnosticViewContext, TView> factory, Action<IDiagnosticViewContext, TView, TState> update)
+internal class DiagnosticViewManager<TView, TState>(
+	Func<IDiagnosticViewContext, TView> factory,
+	Action<IDiagnosticViewContext, TView, TState> update)
 	where TView : FrameworkElement
 {
 	private event EventHandler<TState>? _changed;