DBus init and usage fixes

src/Avalonia.FreeDesktop/DBusHelper.cs

@@ -7,37 +7,51 @@ namespace Avalonia.FreeDesktop
 {
     internal static class DBusHelper
     {
-        public static Connection? Connection { get; private set; }
+        private static Connection? s_defaultConntection;
+        private static bool s_defaultConnectionFailed;
+        public static Connection? DefaultConnection
+        {
+            get
+            {
+                if (s_defaultConntection == null && !s_defaultConnectionFailed)
+                {
+                    s_defaultConntection = TryCreateNewConnection();
+                    if (s_defaultConntection == null)
+                        s_defaultConnectionFailed = true;
+                }
 
-        public static Connection? TryInitialize(string? dbusAddress = null)
-            => Connection ?? TryCreateNewConnection(dbusAddress);
+                return s_defaultConntection;
+            }
+        }
 
         public static Connection? TryCreateNewConnection(string? dbusAddress = null)
         {
             var oldContext = SynchronizationContext.Current;
+            Connection? conn = null;
             try
             {
-                var conn = new Connection(new ClientConnectionOptions(dbusAddress ?? Address.Session!)
+                SynchronizationContext.SetSynchronizationContext(null);
+                conn = new Connection(new ClientConnectionOptions(dbusAddress ?? Address.Session!)
                 {
-                    AutoConnect = false
+                    AutoConnect = false,
                 });
 
                 // Connect synchronously
                 conn.ConnectAsync().GetAwaiter().GetResult();
-
-                Connection = conn;
+                return conn;
             }
             catch (Exception e)
             {
                 Logger.TryGet(LogEventLevel.Error, "DBUS")
                     ?.Log(null, "Unable to connect to DBus: " + e);
+                conn?.Dispose();
             }
             finally
             {
                 SynchronizationContext.SetSynchronizationContext(oldContext);
             }
 
-            return Connection;
+            return null;
         }
     }
 }

src/Avalonia.FreeDesktop/DBusIme/X11DBusImeHelper.cs

@@ -37,7 +37,7 @@ namespace Avalonia.FreeDesktop.DBusIme
             var factory = DetectInputMethod();
             if (factory is not null)
             {
-                var conn = DBusHelper.TryInitialize();
+                var conn = DBusHelper.DefaultConnection;
                 if (conn is not null)
                 {
                     AvaloniaLocator.CurrentMutable.Bind<IX11InputMethodFactory>().ToConstant(factory(conn));

src/Avalonia.FreeDesktop/DBusMenuExporter.cs

@@ -17,7 +17,7 @@ namespace Avalonia.FreeDesktop
     internal class DBusMenuExporter
     {
         public static ITopLevelNativeMenuExporter? TryCreateTopLevelNativeMenu(IntPtr xid) =>
-            DBusHelper.Connection is null ? null : new DBusMenuExporterImpl(DBusHelper.Connection, xid);
+            DBusHelper.DefaultConnection is {} conn ?  new DBusMenuExporterImpl(conn, xid) : null;
 
         public static INativeMenuExporter TryCreateDetachedNativeMenu(string path, Connection currentConnection) =>
             new DBusMenuExporterImpl(currentConnection, path);

src/Avalonia.FreeDesktop/DBusPlatformSettings.cs

@@ -2,6 +2,7 @@
 using System.Threading.Tasks;
 using Avalonia.Media;
 using Avalonia.Platform;
+using Avalonia.Threading;
 using Tmds.DBus.Protocol;
 using Tmds.DBus.SourceGenerator;
 
@@ -17,10 +18,11 @@ namespace Avalonia.FreeDesktop
 
         public DBusPlatformSettings()
         {
-            if (DBusHelper.Connection is null)
+            if (DBusHelper.DefaultConnection is not {} conn)
                 return;
+            using var restoreContext = AvaloniaSynchronizationContext.Ensure(DispatcherPriority.Input);
 
-            _settings = new OrgFreedesktopPortalSettings(DBusHelper.Connection, "org.freedesktop.portal.Desktop", "/org/freedesktop/portal/desktop");
+            _settings = new OrgFreedesktopPortalSettings(conn, "org.freedesktop.portal.Desktop", "/org/freedesktop/portal/desktop");
             _ = _settings.WatchSettingChangedAsync(SettingsChangedHandler);
             _ = TryGetInitialValuesAsync();
         }

src/Avalonia.FreeDesktop/DBusSystemDialog.cs

@@ -7,6 +7,7 @@ using System.Threading.Tasks;
 using Avalonia.Platform;
 using Avalonia.Platform.Storage;
 using Avalonia.Platform.Storage.FileIO;
+using Avalonia.Threading;
 using Tmds.DBus.Protocol;
 using Tmds.DBus.SourceGenerator;
 
@@ -16,10 +17,12 @@ namespace Avalonia.FreeDesktop
     {
         internal static async Task<IStorageProvider?> TryCreateAsync(IPlatformHandle handle)
         {
-            if (DBusHelper.Connection is null)
+            if (DBusHelper.DefaultConnection is not {} conn)
                 return null;
 
-            var dbusFileChooser = new OrgFreedesktopPortalFileChooser(DBusHelper.Connection, "org.freedesktop.portal.Desktop", "/org/freedesktop/portal/desktop");
+            using var restoreContext = AvaloniaSynchronizationContext.Ensure(DispatcherPriority.Input);
+            
+            var dbusFileChooser = new OrgFreedesktopPortalFileChooser(conn, "org.freedesktop.portal.Desktop", "/org/freedesktop/portal/desktop");
             uint version;
             try
             {
@@ -30,7 +33,7 @@ namespace Avalonia.FreeDesktop
                 return null;
             }
 
-            return new DBusSystemDialog(DBusHelper.Connection, handle, dbusFileChooser, version);
+            return new DBusSystemDialog(conn, handle, dbusFileChooser, version);
         }
 
         private readonly Connection _connection;

src/Avalonia.FreeDesktop/DBusTrayIconImpl.cs

@@ -6,6 +6,7 @@ using System.Threading.Tasks;
 using Avalonia.Controls.Platform;
 using Avalonia.Logging;
 using Avalonia.Platform;
+using Avalonia.Threading;
 using Tmds.DBus.Protocol;
 using Tmds.DBus.SourceGenerator;
 
@@ -39,6 +40,7 @@ namespace Avalonia.FreeDesktop
 
         public DBusTrayIconImpl()
         {
+            using var restoreContext = AvaloniaSynchronizationContext.Ensure(DispatcherPriority.Input);
             _connection = DBusHelper.TryCreateNewConnection();
 
             if (_connection is null)

src/Avalonia.X11/X11Platform.cs

@@ -68,9 +68,6 @@ namespace Avalonia.X11
             Info = new X11Info(Display, DeferredDisplay, useXim);
             Globals = new X11Globals(this);
             Resources = new XResources(this);
-            //TODO: log
-            if (options.UseDBusMenu)
-                DBusHelper.TryInitialize();
 
             IRenderTimer timer = options.ShouldRenderOnUIThread
                ? new UiThreadRenderTimer(60)