applets/window-selector: port to Wayland (#1582)

* applets/window-selector: port to Wayland

* wncklet: fix invalid GtkWindow cast in about dialogs

* wayland/window-selector: fix menu rebuild

* wayland/window-selector: rebuild triggers on the submenu's show signal

9 files changed, 860 insertions, 7 deletions

diff --git a/applets/wncklet/Makefile.am b/applets/wncklet/Makefile.am
index 08a82d11..dfcca241 100644
--- a/applets/wncklet/Makefile.am
+++ b/applets/wncklet/Makefile.am
@@ -42,7 +42,9 @@ WNCKLET_SOURCES += \
 	wayland-backend.c \
 	wayland-backend.h \
 	wayland-workspace.c \
-	wayland-workspace.h
+	wayland-workspace.h \
+	wayland-window-menu.c \
+	wayland-window-menu.h
 
 WNCKLET_LDADD += \
 	$(XFW_LIBS)
diff --git a/applets/wncklet/meson.build b/applets/wncklet/meson.build
index f5c7c155..55d19080 100644
--- a/applets/wncklet/meson.build
+++ b/applets/wncklet/meson.build
@@ -60,6 +60,8 @@ if have_wayland
     'wayland-backend.h',
     'wayland-workspace.c',
     'wayland-workspace.h',
+    'wayland-window-menu.c',
+    'wayland-window-menu.h',
   ]
 endif
 
diff --git a/applets/wncklet/org.mate.panel.Wncklet.mate-panel-applet.desktop.in.in b/applets/wncklet/org.mate.panel.Wncklet.mate-panel-applet.desktop.in.in
index 6a2285af..2b409779 100644
--- a/applets/wncklet/org.mate.panel.Wncklet.mate-panel-applet.desktop.in.in
+++ b/applets/wncklet/org.mate.panel.Wncklet.mate-panel-applet.desktop.in.in
@@ -11,7 +11,7 @@ Description=Switch between open windows using a menu
 # Translators: Do NOT translate or transliterate this text (this is an icon file name)!
 Icon=mate-panel-window-menu
 MateComponentId=OAFIID:MATE_WindowMenuApplet;
-Platforms=X11;
+Platforms=X11;Wayland;
 X-MATE-Bugzilla-Bugzilla=MATE
 X-MATE-Bugzilla-Product=mate-panel
 X-MATE-Bugzilla-Component=window selector
diff --git a/applets/wncklet/showdesktop.c b/applets/wncklet/showdesktop.c
index 9125a59e..d393d6c3 100644
--- a/applets/wncklet/showdesktop.c
+++ b/applets/wncklet/showdesktop.c
@@ -574,7 +574,11 @@ static void display_about_dialog(GtkAction* action, ShowDesktopData* sdd)
 		NULL
 	};
 
-	gtk_show_about_dialog(GTK_WINDOW(sdd->applet),
+	GtkWidget* toplevel = gtk_widget_get_toplevel (sdd->applet);
+	if (!GTK_IS_WINDOW (toplevel))
+		toplevel = NULL;
+
+	gtk_show_about_dialog(toplevel ? GTK_WINDOW(toplevel) : NULL,
 		"program-name", _("Show Desktop Button"),
 		"title", _("About Show Desktop Button"),
 		"authors", authors,
diff --git a/applets/wncklet/wayland-window-menu.c b/applets/wncklet/wayland-window-menu.c
new file mode 100644
index 00000000..5080db15
--- /dev/null
+++ b/applets/wncklet/wayland-window-menu.c
@@ -0,0 +1,789 @@
+/* Wayland backend for the Window Selector applet */
+
+/*
+ * Copyright (C) 2026 MATE Desktop Team
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <config.h>
+
+#ifndef HAVE_WAYLAND
+#error file should only be compiled when HAVE_WAYLAND is enabled
+#endif
+
+#include <gtk/gtk.h>
+#include <gdk/gdkwayland.h>
+#include <glib/gi18n.h>
+#include <libxfce4windowing/libxfce4windowing.h>
+
+#include "wayland-window-menu.h"
+
+#define SELECTOR_MAX_WIDTH 50
+
+/* a window in the drag-and-drop payload is identified in-process by the
+ * XfwWindow pointer, matching the tasklist backend (see wayland-backend.c) */
+static GtkTargetEntry source_targets[] = {
+	{ "application/x-wnck-window-id", 0, 0 }
+};
+
+typedef struct {
+	GtkWidget *menu;
+	GtkWidget *root_item;
+	GtkWidget *image;
+	GtkWidget *submenu;
+	GtkWidget *no_windows_item;
+	GHashTable *window_hash;
+	XfwScreen *screen;
+	XfwWorkspaceManager *workspace_manager;
+} WaylandWindowMenu;
+
+static void rebuild_menu (WaylandWindowMenu *data);
+
+/* ---- Helpers ---- */
+
+static XfwWorkspace *
+get_active_workspace (WaylandWindowMenu *data)
+{
+	GList *workspaces, *l;
+
+	if (!data->workspace_manager)
+		return NULL;
+
+	workspaces = xfw_workspace_manager_list_workspaces (data->workspace_manager);
+	for (l = workspaces; l != NULL; l = l->next)
+	{
+		XfwWorkspace *ws = l->data;
+		XfwWorkspaceState state = xfw_workspace_get_state (ws);
+		if (state & XFW_WORKSPACE_STATE_ACTIVE)
+			return ws;
+	}
+
+	return NULL;
+}
+
+static void
+update_root_icon (WaylandWindowMenu *data)
+{
+	XfwWindow *window;
+	GIcon *icon = NULL;
+
+	window = xfw_screen_get_active_window (data->screen);
+	if (window)
+	{
+		XfwApplication *app = xfw_window_get_application (window);
+		if (app)
+			icon = xfw_application_get_gicon (app);
+		if (icon == NULL)
+			icon = xfw_window_get_gicon (window);
+	}
+
+	if (icon != NULL)
+		gtk_image_set_from_gicon (GTK_IMAGE (data->image), icon,
+		                        GTK_ICON_SIZE_LARGE_TOOLBAR);
+	else
+		gtk_image_set_from_icon_name (GTK_IMAGE (data->image),
+		                            "mate-panel-window-menu",
+		                            GTK_ICON_SIZE_LARGE_TOOLBAR);
+}
+
+/* ---- Per-window signal handlers ---- */
+
+static void
+on_menu_item_activate (GtkMenuItem *item, XfwWindow *window)
+{
+	xfw_window_activate (window, NULL,
+	                      gtk_get_current_event_time (), NULL);
+}
+
+static void
+on_drag_begin (GtkWidget *widget, GdkDragContext *context, XfwWindow *window)
+{
+	GdkPixbuf *icon;
+	gint scale = gtk_widget_get_scale_factor (widget);
+
+	icon = xfw_window_get_icon (window, 16, scale);
+	if (icon != NULL)
+		gtk_drag_set_icon_pixbuf (context, icon, 0, 0);
+}
+
+static void
+on_drag_data_get (GtkWidget *widget, GdkDragContext *context,
+                  GtkSelectionData *selection_data, guint info, guint time,
+                  XfwWindow *window)
+{
+	gulong wid = (gulong) window;
+	gtk_selection_data_set (selection_data,
+	                        gtk_selection_data_get_target (selection_data),
+	                        8, (guchar *) &wid, sizeof (wid));
+}
+
+static void
+set_icon_dimmed (GtkWidget *image, gboolean dimmed)
+{
+	GtkStyleContext *context = gtk_widget_get_style_context (image);
+
+	if (dimmed)
+		gtk_style_context_add_class (context, "wnck-selector-dimmed");
+	else
+		gtk_style_context_remove_class (context, "wnck-selector-dimmed");
+}
+
+static void
+on_window_name_changed (XfwWindow *window, GtkWidget *item)
+{
+	GtkWidget *label = g_object_get_data (G_OBJECT (item), "label-widget");
+	const char *name;
+
+	if (label == NULL)
+		return;
+
+	name = xfw_window_get_name (window);
+	if (name == NULL)
+		name = "";
+	gtk_label_set_label (GTK_LABEL (label), name);
+}
+
+static void
+on_window_icon_changed (XfwWindow *window, GtkWidget *item)
+{
+	GtkWidget *image = g_object_get_data (G_OBJECT (item), "icon-widget");
+	GIcon *icon = NULL;
+	XfwApplication *app;
+
+	if (image == NULL)
+		return;
+
+	app = xfw_window_get_application (window);
+	if (app != NULL)
+		icon = xfw_application_get_gicon (app);
+	if (icon == NULL)
+		icon = xfw_window_get_gicon (window);
+
+	if (icon != NULL)
+		gtk_image_set_from_gicon (GTK_IMAGE (image), icon,
+		                        GTK_ICON_SIZE_MENU);
+	else
+		gtk_image_set_from_icon_name (GTK_IMAGE (image), "unknown",
+		                            GTK_ICON_SIZE_MENU);
+}
+
+static void
+on_window_state_changed (XfwWindow *window, XfwWindowState changed_mask,
+                         XfwWindowState new_state, GtkWidget *item)
+{
+	if (changed_mask & XFW_WINDOW_STATE_SKIP_TASKLIST)
+	{
+		if (xfw_window_is_skip_tasklist (window))
+			gtk_widget_hide (item);
+		else
+			gtk_widget_show (item);
+	}
+
+	if (changed_mask & XFW_WINDOW_STATE_URGENT)
+	{
+		GtkWidget *label = g_object_get_data (G_OBJECT (item),
+		                                     "label-widget");
+		if (label == NULL)
+			return;
+
+		if (xfw_window_is_urgent (window))
+		{
+			PangoAttrList *attrs = pango_attr_list_new ();
+			pango_attr_list_insert (attrs,
+			                        pango_attr_weight_new (PANGO_WEIGHT_BOLD));
+			gtk_label_set_attributes (GTK_LABEL (label), attrs);
+			pango_attr_list_unref (attrs);
+		}
+		else
+		{
+			gtk_label_set_attributes (GTK_LABEL (label), NULL);
+		}
+	}
+
+	if (changed_mask & XFW_WINDOW_STATE_MINIMIZED)
+	{
+		GtkWidget *image = g_object_get_data (G_OBJECT (item),
+		                                      "icon-widget");
+		if (image != NULL)
+			set_icon_dimmed (image,
+			                 (new_state & XFW_WINDOW_STATE_MINIMIZED) != 0);
+	}
+}
+
+/* ---- Menu item creation ---- */
+
+static GtkWidget *
+create_window_item (WaylandWindowMenu *data, XfwWindow *window)
+{
+	GtkWidget *item, *box, *image, *label;
+	const char *name;
+	GIcon *icon = NULL;
+	XfwApplication *app;
+	XfwWindowState state;
+	PangoAttrList *attrs;
+
+	name = xfw_window_get_name (window);
+	if (name == NULL)
+		name = "";
+
+	/* Keep the window alive while it is tracked by the menu */
+	g_object_ref (window);
+
+	item = gtk_menu_item_new ();
+	box = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 4);
+
+	/* icon */
+	image = gtk_image_new ();
+	app = xfw_window_get_application (window);
+	if (app != NULL)
+		icon = xfw_application_get_gicon (app);
+	if (icon == NULL)
+		icon = xfw_window_get_gicon (window);
+
+	if (icon != NULL)
+		gtk_image_set_from_gicon (GTK_IMAGE (image), icon,
+		                        GTK_ICON_SIZE_MENU);
+	else
+		gtk_image_set_from_icon_name (GTK_IMAGE (image), "unknown",
+		                            GTK_ICON_SIZE_MENU);
+
+	/* label */
+	label = gtk_label_new (name);
+	gtk_label_set_ellipsize (GTK_LABEL (label), PANGO_ELLIPSIZE_END);
+	gtk_label_set_max_width_chars (GTK_LABEL (label), SELECTOR_MAX_WIDTH);
+	gtk_label_set_xalign (GTK_LABEL (label), 0.0);
+
+	/* bold for urgent windows */
+	state = xfw_window_get_state (window);
+	if (state & XFW_WINDOW_STATE_URGENT)
+	{
+		attrs = pango_attr_list_new ();
+		pango_attr_list_insert (attrs,
+		                        pango_attr_weight_new (PANGO_WEIGHT_BOLD));
+		gtk_label_set_attributes (GTK_LABEL (label), attrs);
+		pango_attr_list_unref (attrs);
+	}
+
+	/* dimmed for minimized windows */
+	if (state & XFW_WINDOW_STATE_MINIMIZED)
+		set_icon_dimmed (image, TRUE);
+
+	gtk_box_pack_start (GTK_BOX (box), image, FALSE, FALSE, 2);
+	gtk_box_pack_start (GTK_BOX (box), label, TRUE, TRUE, 2);
+	gtk_container_add (GTK_CONTAINER (item), box);
+
+	g_object_set_data (G_OBJECT (item), "icon-widget", image);
+	g_object_set_data (G_OBJECT (item), "label-widget", label);
+
+	g_signal_connect (item, "activate",
+	                  G_CALLBACK (on_menu_item_activate), window);
+
+	g_signal_connect (window, "name-changed",
+	                  G_CALLBACK (on_window_name_changed), item);
+	g_signal_connect (window, "icon-changed",
+	                  G_CALLBACK (on_window_icon_changed), item);
+	g_signal_connect (window, "state-changed",
+	                  G_CALLBACK (on_window_state_changed), item);
+
+	/* drag the menu item to move the window (matches WnckSelector) */
+	gtk_drag_source_set (item, GDK_BUTTON1_MASK,
+	                     source_targets, G_N_ELEMENTS (source_targets),
+	                     GDK_ACTION_MOVE);
+	g_signal_connect (item, "drag-begin",
+	                  G_CALLBACK (on_drag_begin), window);
+	g_signal_connect (item, "drag-data-get",
+	                  G_CALLBACK (on_drag_data_get), window);
+
+	g_hash_table_insert (data->window_hash, window, item);
+
+	gtk_widget_show_all (item);
+	return item;
+}
+
+static void
+append_window_item (WaylandWindowMenu *data, XfwWindow *window)
+{
+	GtkWidget *item = create_window_item (data, window);
+	gtk_menu_shell_append (GTK_MENU_SHELL (data->submenu), item);
+}
+
+static void
+add_workspace_label (WaylandWindowMenu *data, XfwWorkspace *ws)
+{
+	GtkWidget *item, *label;
+	const char *ws_name;
+	char *markup;
+
+	ws_name = xfw_workspace_get_name (ws);
+	if (ws_name == NULL || ws_name[0] == '\0')
+		ws_name = xfw_workspace_get_id (ws);
+
+	item = gtk_separator_menu_item_new ();
+	label = gtk_label_new ("");
+
+	markup = g_markup_printf_escaped ("<span size=\"small\" style=\"italic\">%s</span>",
+	                                  ws_name);
+	gtk_label_set_markup (GTK_LABEL (label), markup);
+	gtk_label_set_xalign (GTK_LABEL (label), 1.0);
+	g_free (markup);
+
+	gtk_widget_show (label);
+	gtk_container_add (GTK_CONTAINER (item), label);
+	gtk_menu_shell_append (GTK_MENU_SHELL (data->submenu), item);
+}
+
+/* ---- Disconnect / rebuild ---- */
+
+static void
+disconnect_window_signals (WaylandWindowMenu *data)
+{
+	GHashTableIter iter;
+	gpointer key, value;
+
+	g_hash_table_iter_init (&iter, data->window_hash);
+	while (g_hash_table_iter_next (&iter, &key, &value))
+		g_signal_handlers_disconnect_by_data (key, value);
+
+	g_hash_table_remove_all (data->window_hash);
+}
+
+static void
+rebuild_menu (WaylandWindowMenu *data)
+{
+	GList *children, *l, *wins, *workspaces, *wl;
+	XfwWorkspace *active_ws;
+	gboolean added_separator;
+
+	/* 1. Disconnect per-window signals from previous menu items */
+	disconnect_window_signals (data);
+
+	/* 2. Remove all existing children from the submenu */
+	children = gtk_container_get_children (GTK_CONTAINER (data->submenu));
+	for (l = children; l != NULL; l = l->next)
+		gtk_widget_destroy (GTK_WIDGET (l->data));
+	g_list_free (children);
+
+	data->no_windows_item = NULL;
+
+	wins = xfw_screen_get_windows_stacked (data->screen);
+	active_ws = get_active_workspace (data);
+
+	if (data->workspace_manager == NULL)
+	{
+		/* No workspace support: flat list of all windows */
+		for (l = wins; l != NULL; l = l->next)
+		{
+			XfwWindow *w = l->data;
+			if (xfw_window_is_skip_tasklist (w))
+				continue;
+			append_window_item (data, w);
+		}
+	}
+	else
+	{
+		/* Add pinned + current workspace windows first */
+		for (l = wins; l != NULL; l = l->next)
+		{
+			XfwWindow *w = l->data;
+			XfwWorkspace *ws;
+
+			if (xfw_window_is_skip_tasklist (w))
+				continue;
+
+			ws = xfw_window_get_workspace (w);
+			/* Windows whose workspace is not known yet report NULL; keep
+			 * them in the current-workspace group so they aren't dropped */
+			if (xfw_window_is_pinned (w) ||
+			    ws == NULL ||
+			    ws == active_ws)
+			{
+				append_window_item (data, w);
+			}
+		}
+
+		/* Add other workspace sections */
+		added_separator = FALSE;
+
+		workspaces = xfw_workspace_manager_list_workspaces (
+			data->workspace_manager);
+
+		for (wl = workspaces; wl != NULL; wl = wl->next)
+		{
+			XfwWorkspace *ws = wl->data;
+			XfwWorkspaceState ws_state;
+			gboolean has_windows;
+			GList *wwl;
+
+			if (ws == active_ws)
+				continue;
+
+			ws_state = xfw_workspace_get_state (ws);
+			if (ws_state & XFW_WORKSPACE_STATE_HIDDEN)
+				continue;
+
+			/* Check if this workspace has any windows */
+			has_windows = FALSE;
+			for (wwl = wins; wwl != NULL; wwl = wwl->next)
+			{
+				XfwWindow *w = wwl->data;
+				if (xfw_window_is_skip_tasklist (w))
+					continue;
+				if (xfw_window_get_workspace (w) == ws)
+				{
+					has_windows = TRUE;
+					break;
+				}
+			}
+
+			if (!has_windows)
+				continue;
+
+			if (!added_separator)
+			{
+				GtkWidget *sep =
+					gtk_separator_menu_item_new ();
+				gtk_menu_shell_append (
+					GTK_MENU_SHELL (data->submenu),
+					sep);
+				added_separator = TRUE;
+			}
+
+			add_workspace_label (data, ws);
+
+			for (wwl = wins; wwl != NULL; wwl = wwl->next)
+			{
+				XfwWindow *w = wwl->data;
+				if (xfw_window_is_skip_tasklist (w))
+					continue;
+				if (xfw_window_get_workspace (w) == ws)
+					append_window_item (data, w);
+			}
+		}
+	}
+
+	/* "No Windows Open" item */
+	{
+		GtkWidget *item;
+
+		item = gtk_menu_item_new_with_label (_ ("No Windows Open"));
+		gtk_widget_set_sensitive (item, FALSE);
+		gtk_menu_shell_append (GTK_MENU_SHELL (data->submenu), item);
+		data->no_windows_item = item;
+
+		if (g_hash_table_size (data->window_hash) > 0)
+			gtk_widget_hide (item);
+		else
+			gtk_widget_show (item);
+	}
+}
+
+/* ---- Screen signal handlers (live updates while menu is visible) ---- */
+
+static void
+on_window_opened (XfwScreen *screen, XfwWindow *window,
+                  WaylandWindowMenu *data)
+{
+	/* refresh the button icon for the initially-enumerated windows too */
+	update_root_icon (data);
+
+	if (!gtk_widget_get_mapped (data->submenu))
+		return;
+
+	if (g_hash_table_contains (data->window_hash, window))
+		return;
+
+	if (xfw_window_is_skip_tasklist (window))
+		return;
+
+	append_window_item (data, window);
+	gtk_menu_reposition (GTK_MENU (data->submenu));
+
+	if (data->no_windows_item != NULL)
+		gtk_widget_hide (data->no_windows_item);
+}
+
+static void
+on_window_closed (XfwScreen *screen, XfwWindow *window,
+                  WaylandWindowMenu *data)
+{
+	GtkWidget *item;
+
+	if (!gtk_widget_get_mapped (data->submenu))
+		return;
+
+	item = g_hash_table_lookup (data->window_hash, window);
+	if (item == NULL)
+		return;
+
+	g_signal_handlers_disconnect_by_data (window, item);
+	g_hash_table_remove (data->window_hash, window);
+	gtk_widget_destroy (item);
+	gtk_menu_reposition (GTK_MENU (data->submenu));
+
+	if (g_hash_table_size (data->window_hash) == 0 &&
+	    data->no_windows_item != NULL)
+	{
+		gtk_widget_show (data->no_windows_item);
+	}
+}
+
+static void
+on_active_window_changed (XfwScreen *screen, XfwWindow *previous_window,
+                          WaylandWindowMenu *data)
+{
+	update_root_icon (data);
+}
+
+/* ---- Workspace manager signal handlers ---- */
+
+static void
+on_workspace_created (XfwWorkspaceManager *manager, XfwWorkspace *workspace,
+                      WaylandWindowMenu *data)
+{
+	/* Defer to next rebuild; the menu groups by workspace. */
+}
+
+static void
+on_workspace_destroyed (XfwWorkspaceManager *manager, XfwWorkspace *workspace,
+                        WaylandWindowMenu *data)
+{
+	/* Defer to next rebuild. */
+}
+
+/* ---- Scroll event for window switching ---- */
+
+static gboolean
+on_scroll_event (GtkWidget *widget, GdkEventScroll *event,
+                 WaylandWindowMenu *data)
+{
+	XfwWorkspace *active_ws;
+	GList *windows, *l;
+	GdkScrollDirection direction;
+	XfwWindow *prev;
+	gboolean found_active;
+
+	if (event->direction == GDK_SCROLL_SMOOTH)
+	{
+		if (event->delta_y < 0)
+			direction = GDK_SCROLL_UP;
+		else if (event->delta_y > 0)
+			direction = GDK_SCROLL_DOWN;
+		else
+			return TRUE;
+	}
+	else
+	{
+		direction = event->direction;
+	}
+
+	if (direction != GDK_SCROLL_UP && direction != GDK_SCROLL_DOWN)
+		return TRUE;
+
+	active_ws = get_active_workspace (data);
+	windows = xfw_screen_get_windows_stacked (data->screen);
+
+	prev = NULL;
+	found_active = FALSE;
+
+	for (l = windows; l != NULL; l = l->next)
+	{
+		XfwWindow *w = l->data;
+
+		if (xfw_window_is_skip_tasklist (w))
+			continue;
+
+		if (active_ws != NULL && !xfw_window_is_pinned (w) &&
+		    !xfw_window_is_on_workspace (w, active_ws))
+		{
+			continue;
+		}
+
+		if (xfw_window_is_active (w))
+		{
+			if (direction == GDK_SCROLL_UP && prev != NULL)
+			{
+				xfw_window_activate (prev, NULL,
+				                     event->time, NULL);
+				return TRUE;
+			}
+			if (direction == GDK_SCROLL_DOWN)
+				found_active = TRUE;
+			continue;
+		}
+
+		if (found_active)
+		{
+			xfw_window_activate (w, NULL, event->time, NULL);
+			return TRUE;
+		}
+
+		prev = w;
+	}
+
+	/* Wrapping: if scrolling up at the beginning, activate last window */
+	if (direction == GDK_SCROLL_UP && prev != NULL)
+	{
+		xfw_window_activate (prev, NULL, event->time, NULL);
+		return TRUE;
+	}
+
+	return TRUE;
+}
+
+/* ---- Menu show handler ---- */
+
+static void
+on_menu_show (GtkWidget *menu, WaylandWindowMenu *data)
+{
+	rebuild_menu (data);
+}
+
+/* ---- Cleanup ---- */
+
+static void
+wayland_window_menu_free (WaylandWindowMenu *data)
+{
+	if (data->window_hash != NULL)
+	{
+		disconnect_window_signals (data);
+		g_hash_table_destroy (data->window_hash);
+		data->window_hash = NULL;
+	}
+
+	if (data->workspace_manager != NULL)
+	{
+		/* borrowed from the screen: only disconnect, do not unref */
+		g_signal_handlers_disconnect_by_data (data->workspace_manager,
+		                                      data);
+		data->workspace_manager = NULL;
+	}
+
+	if (data->screen != NULL)
+	{
+		g_signal_handlers_disconnect_by_data (data->screen, data);
+		g_object_unref (data->screen);
+		data->screen = NULL;
+	}
+
+	g_free (data);
+}
+
+/* ---- Public API ---- */
+
+GtkWidget *
+wayland_window_menu_new (void)
+{
+	WaylandWindowMenu *data;
+	XfwScreen *screen;
+	GdkDisplay *display;
+	GtkCssProvider *provider;
+
+	display = gdk_display_get_default ();
+	if (display == NULL || !GDK_IS_WAYLAND_DISPLAY (display))
+		return gtk_label_new (_ ("[Window menu not supported on this platform]"));
+
+	xfw_set_client_type (XFW_CLIENT_TYPE_PAGER);
+
+	screen = xfw_screen_get_default ();
+	if (screen == NULL)
+		return gtk_label_new (_ ("[Shell does not support "
+		                         "WLR Foreign Toplevel Control]"));
+
+	data = g_new0 (WaylandWindowMenu, 1);
+	/* xfw_screen_get_default() returns a referenced screen */
+	data->screen = screen;
+	data->window_hash = g_hash_table_new_full (g_direct_hash,
+	                                           g_direct_equal,
+	                                           g_object_unref,
+	                                           NULL);
+
+	/* borrowed from the screen, which we keep alive */
+	data->workspace_manager = xfw_screen_get_workspace_manager (screen);
+
+	/* Build the menubar (matches WnckSelector's GtkMenuBar structure) */
+	data->menu = gtk_menu_bar_new ();
+
+	/* Root item: icon of active window */
+	data->root_item = gtk_menu_item_new ();
+	data->image = gtk_image_new ();
+	gtk_container_add (GTK_CONTAINER (data->root_item), data->image);
+
+	/* Submenu: the actual window list */
+	data->submenu = gtk_menu_new ();
+	gtk_menu_item_set_submenu (GTK_MENU_ITEM (data->root_item),
+	                           data->submenu);
+	gtk_menu_shell_append (GTK_MENU_SHELL (data->menu), data->root_item);
+
+	/* Remove menubar borders to match panel aesthetics; the
+	 * dimmed-window icon style is needed inside the popup submenu,
+	 * which is a separate window, so use a screen-wide provider */
+	gtk_widget_set_name (data->menu, "wnck-selector-menubar");
+	provider = gtk_css_provider_new ();
+	gtk_css_provider_load_from_data (provider,
+	                                 "#wnck-selector-menubar {\n"
+	                                 "  border-width: 0px;\n"
+	                                 "}\n"
+	                                 ".wnck-selector-dimmed {\n"
+	                                 "  opacity: 0.5;\n"
+	                                 "}",
+	                                 -1, NULL);
+	gtk_style_context_add_provider_for_screen (
+		gtk_widget_get_screen (data->menu),
+		GTK_STYLE_PROVIDER (provider),
+		GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
+	g_object_unref (provider);
+
+	g_object_set_data_full (G_OBJECT (data->menu),
+	                        "wayland_window_menu_data",
+	                        data,
+	                        (GDestroyNotify) wayland_window_menu_free);
+
+	g_signal_connect (data->submenu, "show",
+	                  G_CALLBACK (on_menu_show), data);
+
+	/* Screen signals for live updates while menu is visible */
+	g_signal_connect (data->screen, "window-opened",
+	                  G_CALLBACK (on_window_opened), data);
+	g_signal_connect (data->screen, "window-closed",
+	                  G_CALLBACK (on_window_closed), data);
+	g_signal_connect (data->screen, "active-window-changed",
+	                  G_CALLBACK (on_active_window_changed), data);
+
+	/* Workspace manager signals */
+	if (data->workspace_manager != NULL)
+	{
+		g_signal_connect (data->workspace_manager,
+		                  "workspace-created",
+		                  G_CALLBACK (on_workspace_created), data);
+		g_signal_connect (data->workspace_manager,
+		                  "workspace-destroyed",
+		                  G_CALLBACK (on_workspace_destroyed), data);
+	}
+
+	/* Set initial root icon to active window */
+	update_root_icon (data);
+
+	/* Scroll-to-switch-windows */
+	gtk_widget_add_events (data->menu, GDK_SCROLL_MASK);
+	g_signal_connect (data->menu, "scroll-event",
+	                  G_CALLBACK (on_scroll_event), data);
+
+	gtk_widget_show (data->root_item);
+	gtk_widget_show (data->image);
+	gtk_widget_show (data->menu);
+	return data->menu;
+}
diff --git a/applets/wncklet/wayland-window-menu.h b/applets/wncklet/wayland-window-menu.h
new file mode 100644
index 00000000..2a1d39f0
--- /dev/null
+++ b/applets/wncklet/wayland-window-menu.h
@@ -0,0 +1,43 @@
+/* Wayland backend for the Window Selector applet */
+
+/*
+ * Copyright (C) 2026 MATE Desktop Team
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef _WNCKLET_APPLET_WAYLAND_WINDOW_MENU_H_
+#define _WNCKLET_APPLET_WAYLAND_WINDOW_MENU_H_
+
+#ifdef PACKAGE_NAME
+#ifndef HAVE_WAYLAND
+#error file should only be included when HAVE_WAYLAND is enabled
+#endif
+#endif
+
+#include <gtk/gtk.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+GtkWidget *wayland_window_menu_new (void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _WNCKLET_APPLET_WAYLAND_WINDOW_MENU_H_ */
diff --git a/applets/wncklet/window-list.c b/applets/wncklet/window-list.c
index a880b26b..cc09c417 100644
--- a/applets/wncklet/window-list.c
+++ b/applets/wncklet/window-list.c
@@ -1055,7 +1055,11 @@ static void display_about_dialog(GtkAction* action, TasklistData* tasklist)
 		NULL
 	};
 
-	gtk_show_about_dialog(GTK_WINDOW(tasklist->applet),
+	GtkWidget* toplevel = gtk_widget_get_toplevel (tasklist->applet);
+	if (!GTK_IS_WINDOW (toplevel))
+		toplevel = NULL;
+
+	gtk_show_about_dialog(toplevel ? GTK_WINDOW(toplevel) : NULL,
 		"program-name", _("Window List"),
 		"title", _("About Window List"),
 		"authors", authors,
diff --git a/applets/wncklet/window-menu.c b/applets/wncklet/window-menu.c
index 18f33f19..21d2117f 100644
--- a/applets/wncklet/window-menu.c
+++ b/applets/wncklet/window-menu.c
@@ -43,6 +43,7 @@
 
 #ifdef HAVE_WAYLAND
 #include <gdk/gdkwayland.h>
+#include "wayland-window-menu.h"
 #endif /* HAVE_WAYLAND */
 
 #ifndef HAVE_X11
@@ -86,7 +87,11 @@ static void window_menu_about(GtkAction* action, WindowMenu* window_menu)
 		NULL
 	};
 
-	gtk_show_about_dialog(GTK_WINDOW(window_menu->applet),
+	GtkWidget* toplevel = gtk_widget_get_toplevel (window_menu->applet);
+	if (!GTK_IS_WINDOW (toplevel))
+		toplevel = NULL;
+
+	gtk_show_about_dialog(toplevel ? GTK_WINDOW(toplevel) : NULL,
 		"program-name", _("Window Selector"),
 		"title", _("About Window Selector"),
 		"authors", authors,
@@ -271,7 +276,7 @@ gboolean window_menu_applet_fill(MatePanelApplet* applet)
 #ifdef HAVE_WAYLAND
 	if (GDK_IS_WAYLAND_DISPLAY (gdk_display_get_default ()))
 	{
-		window_menu->selector = gtk_label_new ("[Window menu not supported on Wayland]");
+		window_menu->selector = wayland_window_menu_new ();
 	}
 	else
 #endif /* HAVE_WAYLAND */
diff --git a/applets/wncklet/workspace-switcher.c b/applets/wncklet/workspace-switcher.c
index 93318314..b4ae493d 100644
--- a/applets/wncklet/workspace-switcher.c
+++ b/applets/wncklet/workspace-switcher.c
@@ -990,7 +990,11 @@ static void display_about_dialog(GtkAction* action, PagerData* pager)
 		NULL
 	};
 
-	gtk_show_about_dialog(GTK_WINDOW(pager->applet),
+	GtkWidget* toplevel = gtk_widget_get_toplevel (pager->applet);
+	if (!GTK_IS_WINDOW (toplevel))
+		toplevel = NULL;
+
+	gtk_show_about_dialog(toplevel ? GTK_WINDOW(toplevel) : NULL,
 		"program-name", _("Workspace Switcher"),
 		"title", _("About Workspace Switcher"),
 		"authors", authors,