Feature: Drag files from LinuxFiles into other apps on Wayland

src/Files.App/MainWindow.Linux.cs

@@ -26,9 +26,9 @@ public sealed partial class MainWindow
 #if UNO_WAYLAND
 		private bool _waylandWindow;
 		// The Wayland host implements caption regions, move and maximize itself (InputNonClientPointerSource, presenter).
-		private bool IsWaylandWindow => _waylandWindow;
+		internal bool IsWaylandWindow => _waylandWindow;
 #else
-		private static bool IsWaylandWindow => false;
+		internal bool IsWaylandWindow => false;
 #endif
 		public bool UseClientSideDecorations => OperatingSystem.IsLinux() &&
 			Ioc.Default.GetRequiredService<ILocalSettingsStore>().Get("UseClientSideDecorations", true);

src/Files.App/Platforms/Desktop/Services/DesktopFileDragHelper.cs

@@ -91,6 +91,24 @@ public static async Task<bool> TryPasteFilesAsync(string destinationPath, IShell
 			}
 		}
 
+		/// <summary>
+		/// Makes a drag of <paramref name="paths"/> available to other applications. On the native Wayland host the dragged
+		/// <paramref name="data"/> carries the file list (<c>text/uri-list</c>) and the host offers it to the compositor once the
+		/// pointer leaves the window; on X11 the Files selection host follows the pointer instead.
+		/// </summary>
+		public static void StartDrag(DataPackage data, IEnumerable<string?> paths)
+		{
+			if (!MainWindow.Instance.IsWaylandWindow)
+			{
+				StartExternalDrag(paths);
+				return;
+			}
+
+			var existing = ExistingPaths(paths);
+			if (existing.Count > 0)
+				data.SetData(Files.Platform.Linux.Clipboard.ClipboardFormats.UriList, Files.Platform.Linux.Clipboard.ClipboardFormats.BuildUriList(existing));
+		}
+
 		/// <summary>
 		/// Starts offering the dragged items to other applications while the pointer is outside this window. Returns immediately; the
 		/// drag source follows the pointer until the primary button is released.

src/Files.App/UserControls/Pane/ShelfPane.xaml.cs

@@ -69,7 +69,7 @@ private void ListView_DragItemsStarting(object sender, DragItemsStartingEventArg
 				return;
 
 			e.Data.Properties["Files_ActionBinder"] = "Files_ShelfBinder";
-			Files.App.Services.Desktop.DesktopFileDragHelper.StartExternalDrag(paths);
+			Files.App.Services.Desktop.DesktopFileDragHelper.StartDrag(e.Data, paths);
 		}
 
 		private void ShelfItemsList_RightTapped(object sender, Microsoft.UI.Xaml.Input.RightTappedRoutedEventArgs e)

src/Files.App/Utils/Storage/Operations/FilesystemHelpers.Linux.cs

@@ -20,8 +20,13 @@ public static async Task<IEnumerable<IStorageItemWithPath>> GetDraggedStorageIte
 				IEnumerable<string> paths;
 				if (packageView.Contains(ClipboardFormats.UriList))
 				{
-					var data = await packageView.GetDataAsync(ClipboardFormats.UriList);
-					paths = data is string text ? ClipboardFormats.ParseUriList(text) : [];
+					// Uno's X11 host exposes the list as text, the Wayland host as the raw bytes it received.
+					paths = await packageView.GetDataAsync(ClipboardFormats.UriList) switch
+					{
+						string text => ClipboardFormats.ParseUriList(text),
+						byte[] bytes => ClipboardFormats.ParseUriList(System.Text.Encoding.UTF8.GetString(bytes)),
+						_ => [],
+					};
 				}
 				else if (packageView.Contains(StandardDataFormats.StorageItems))
 				{

src/Files.App/Views/Layouts/BaseLayoutPage.cs

@@ -1160,7 +1160,7 @@ protected virtual void FileList_DragItemsStarting(object sender, DragItemsStarti
 				// Set can window to front (#13255)
 				MainWindow.Instance.SetCanWindowToFront(false);
 				itemDragging = true;
-				Files.App.Services.Desktop.DesktopFileDragHelper.StartExternalDrag(orderedItems.Select(x => x.ItemPath));
+				Files.App.Services.Desktop.DesktopFileDragHelper.StartDrag(e.Data, orderedItems.Select(x => x.ItemPath));
 			}
 			catch (Exception)
 			{