diff --git a/client.h b/client.h
index bea7a97..123a584 100644
--- a/client.h
+++ b/client.h
@@ -98,6 +98,8 @@ toplevel_from_wlr_surface(struct wlr_surface *s, Client **pc, LayerSurface **pl)
 			xdg_surface = tmp_xdg_surface;
 			break;
 		case WLR_XDG_SURFACE_ROLE_TOPLEVEL:
+			if (!xdg_surface->toplevel)
+				return -1;
 			c = xdg_surface->data;
 			type = c->type;
 			goto end;
diff --git a/dwl.c b/dwl.c
index e7edaa0..69e4188 100644
--- a/dwl.c
+++ b/dwl.c
@@ -83,7 +83,6 @@
 #define VISIBLEON(C, M)         ((M) && (C)->mon == (M) && ((C)->tags & (M)->tagset[(M)->seltags]))
 #define TAGMASK                 ((1u << TAGCOUNT) - 1)
 #define LISTEN(E, L, H)         wl_signal_add((E), ((L)->notify = (H), (L)))
-#define LISTEN_STATIC(E, H, D)  do { StaticListener *_l = ecalloc(1, sizeof(*_l)); _l->listener.notify = (H); _l->data = (D); wl_signal_add((E), &_l->listener); } while (0)
 
 /* enums */
 enum { CurNormal, CurPressed, CurMove, CurResize }; /* cursor */
@@ -246,6 +245,17 @@ typedef struct {
 	struct wl_listener destroy;
 } PointerConstraint;
 
+typedef struct {
+	struct wlr_idle_inhibitor_v1 *inhibitor;
+	struct wl_listener destroy;
+} IdleInhibitor;
+
+typedef struct {
+	struct wlr_xdg_popup *popup;
+	struct wl_listener commit;
+	struct wl_listener destroy;
+} Popup;
+
 typedef struct {
 	const char *id;
 	const char *title;
@@ -263,12 +273,6 @@ typedef struct {
 	struct wl_listener destroy;
 } SessionLock;
 
-typedef struct {
-	/* Must keep this field first */
-	struct wl_listener listener;
-	void *data;
-} StaticListener;
-
 /* function declarations */
 static void applybounds(Client *c, struct wlr_box *bbox);
 static void applygeom(Client *c);
@@ -304,6 +308,7 @@ static void createpopup(struct wl_listener *listener, void *data);
 static void cursorconstrain(struct wlr_pointer_constraint_v1 *constraint);
 static void cursorframe(struct wl_listener *listener, void *data);
 static void cursorwarptohint(void);
+static void destroybackend(struct wl_listener *listener, void *data);
 static void destroydecoration(struct wl_listener *listener, void *data);
 static void destroydragicon(struct wl_listener *listener, void *data);
 static void destroyidleinhibitor(struct wl_listener *listener, void *data);
@@ -312,6 +317,7 @@ static void destroylock(SessionLock *lock, int unlocked);
 static void destroylocksurface(struct wl_listener *listener, void *data);
 static void destroynotify(struct wl_listener *listener, void *data);
 static void destroypointerconstraint(struct wl_listener *listener, void *data);
+static void destroypopup(struct wl_listener *listener, void *data);
 static void destroysessionlock(struct wl_listener *listener, void *data);
 static void destroykeyboardgroup(struct wl_listener *listener, void *data);
 static Monitor *dirtomon(enum wlr_direction dir);
@@ -319,6 +325,7 @@ static void focusclient(Client *c, LayerSurface *l, int lift);
 static void focusmon(const Arg *arg);
 static void focusstack(const Arg *arg);
 static Client *focustop(Monitor *m);
+static void forgetoffmons(void);
 static void fullscreennotify(struct wl_listener *listener, void *data);
 static void gpureset(struct wl_listener *listener, void *data);
 static void handlesig(int signo);
@@ -461,6 +468,7 @@ static struct wl_array ghosts; /* struct wlr_scene_node *, unmapped clients */
 static struct wl_array offmons; /* char *, names of outputs turned off by clients */
 
 /* global event handlers */
+static struct wl_listener backend_destroy = {.notify = destroybackend};
 static struct wl_listener cursor_axis = {.notify = axisnotify};
 static struct wl_listener cursor_button = {.notify = buttonpress};
 static struct wl_listener cursor_frame = {.notify = cursorframe};
@@ -855,7 +863,8 @@ cleanup(void)
 
 	/* If it's not destroyed manually, it will cause a use-after-free of wlr_seat.
 	 * Destroy it until it's fixed on the wlroots side */
-	wlr_backend_destroy(backend);
+	if (backend)
+		wlr_backend_destroy(backend);
 
 	if (transaction_idle)
 		wl_event_source_remove(transaction_idle);
@@ -911,6 +920,7 @@ cleanuplisteners(void)
 	wl_list_remove(&new_idle_inhibitor.link);
 	wl_list_remove(&layout_change.link);
 	wl_list_remove(&new_input_device.link);
+	wl_list_remove(&backend_destroy.link);
 	wl_list_remove(&new_virtual_keyboard.link);
 	wl_list_remove(&new_virtual_pointer.link);
 	wl_list_remove(&new_pointer_constraint.link);
@@ -1054,8 +1064,8 @@ commitnotify(struct wl_listener *listener, void *data)
 void
 commitpopup(struct wl_listener *listener, void *data)
 {
-	StaticListener *sl = wl_container_of(listener, sl, listener);
-	struct wlr_xdg_popup *popup = sl->data;
+	Popup *p = wl_container_of(listener, p, commit);
+	struct wlr_xdg_popup *popup = p->popup;
 	LayerSurface *l = NULL;
 	Client *c = NULL;
 	struct wlr_box box;
@@ -1077,8 +1087,7 @@ commitpopup(struct wl_listener *listener, void *data)
 	box.x -= (type == LayerShell ? l->scene->node.x : c->geom.x - c->surface.xdg->geometry.x);
 	box.y -= (type == LayerShell ? l->scene->node.y : c->geom.y - c->surface.xdg->geometry.y);
 	wlr_xdg_popup_unconstrain_from_box(popup, &box);
-	wl_list_remove(&listener->link);
-	free(listener);
+	destroypopup(&p->destroy, NULL);
 }
 
 void
@@ -1098,7 +1107,9 @@ void
 createidleinhibitor(struct wl_listener *listener, void *data)
 {
 	struct wlr_idle_inhibitor_v1 *idle_inhibitor = data;
-	LISTEN_STATIC(&idle_inhibitor->events.destroy, destroyidleinhibitor, idle_inhibitor);
+	IdleInhibitor *i = ecalloc(1, sizeof(*i));
+	i->inhibitor = idle_inhibitor;
+	LISTEN(&idle_inhibitor->events.destroy, &i->destroy, destroyidleinhibitor);
 
 	checkidleinhibitor(NULL);
 }
@@ -1372,7 +1383,10 @@ createpopup(struct wl_listener *listener, void *data)
 	/* This event is raised when a client (either xdg-shell or layer-shell)
 	 * creates a new popup. */
 	struct wlr_xdg_popup *popup = data;
-	LISTEN_STATIC(&popup->base->surface->events.commit, commitpopup, popup);
+	Popup *p = ecalloc(1, sizeof(*p));
+	p->popup = popup;
+	LISTEN(&popup->base->surface->events.commit, &p->commit, commitpopup);
+	LISTEN(&popup->events.destroy, &p->destroy, destroypopup);
 }
 
 void
@@ -1413,6 +1427,21 @@ cursorwarptohint(void)
 	}
 }
 
+void
+destroybackend(struct wl_listener *listener, void *data)
+{
+	/* wlroots destroys the backend itself when the session goes away (e.g.
+	 * seatd stopped at shutdown), and asserts that its listeners are gone */
+	wl_list_remove(&new_output.link);
+	wl_list_init(&new_output.link);
+	wl_list_remove(&new_input_device.link);
+	wl_list_init(&new_input_device.link);
+	wl_list_remove(&backend_destroy.link);
+	wl_list_init(&backend_destroy.link);
+	backend = NULL;
+	quit(NULL);
+}
+
 void
 destroydecoration(struct wl_listener *listener, void *data)
 {
@@ -1435,12 +1464,11 @@ destroydragicon(struct wl_listener *listener, void *data)
 void
 destroyidleinhibitor(struct wl_listener *listener, void *data)
 {
-	StaticListener *sl = wl_container_of(listener, sl, listener);
-	struct wlr_idle_inhibitor_v1 *idle_inhibitor = sl->data;
+	IdleInhibitor *i = wl_container_of(listener, i, destroy);
 	/* At this point the idle inhibitor is still in the list of the manager */
-	checkidleinhibitor(wlr_surface_get_root_surface(idle_inhibitor->surface));
-	wl_list_remove(&listener->link);
-	free(listener);
+	checkidleinhibitor(wlr_surface_get_root_surface(i->inhibitor->surface));
+	wl_list_remove(&i->destroy.link);
+	free(i);
 }
 
 void
@@ -1492,14 +1520,21 @@ destroylocksurface(struct wl_listener *listener, void *data)
 	if (lock_surface->surface != seat->keyboard_state.focused_surface)
 		return;
 
-	if (locked && cur_lock && !wl_list_empty(&cur_lock->surfaces)) {
-		surface = wl_container_of(cur_lock->surfaces.next, surface, link);
-		client_notify_enter(surface->surface, wlr_seat_get_keyboard(seat));
-	} else if (!locked) {
+	if (!locked) {
 		focusclient(focustop(selmon), NULL, 1);
-	} else {
-		wlr_seat_keyboard_clear_focus(seat);
+		return;
 	}
+
+	/* The surface being destroyed is still in the list */
+	if (cur_lock) {
+		wl_list_for_each(surface, &cur_lock->surfaces, link) {
+			if (surface != lock_surface) {
+				client_notify_enter(surface->surface, wlr_seat_get_keyboard(seat));
+				return;
+			}
+		}
+	}
+	wlr_seat_keyboard_clear_focus(seat);
 }
 
 void
@@ -1547,6 +1582,15 @@ destroypointerconstraint(struct wl_listener *listener, void *data)
 	free(pointer_constraint);
 }
 
+void
+destroypopup(struct wl_listener *listener, void *data)
+{
+	Popup *p = wl_container_of(listener, p, destroy);
+	wl_list_remove(&p->commit.link);
+	wl_list_remove(&p->destroy.link);
+	free(p);
+}
+
 void
 destroysessionlock(struct wl_listener *listener, void *data)
 {
@@ -1666,6 +1710,8 @@ void
 focusmon(const Arg *arg)
 {
 	int i = 0, nmons = wl_list_length(&mons);
+	if (!selmon)
+		return;
 	if (nmons) {
 		do /* don't switch to disabled mons */
 			selmon = dirtomon(arg->i);
@@ -1706,18 +1752,42 @@ focusstack(const Arg *arg)
 Client *
 focustop(Monitor *m)
 {
-	Client *c;
+	Client *c, *fs = NULL;
 
-	wl_list_for_each(c, &fstack, flink)
-		if (VISIBLEON(c, m) && c->isfullscreen)
-			return c;
+	wl_list_for_each(c, &fstack, flink) {
+		if (VISIBLEON(c, m) && c->isfullscreen) {
+			fs = c;
+			break;
+		}
+	}
 
+	/* A fullscreen client's children are shown above it */
 	wl_list_for_each(c, &fstack, flink)
-		if (VISIBLEON(c, m))
+		if (VISIBLEON(c, m) && (!fs || c == fs || client_get_parent(c) == fs))
 			return c;
 	return NULL;
 }
 
+void
+forgetoffmons(void)
+{
+	/* Forget the outputs that were unplugged while off, or they would stay
+	 * off when plugged in again */
+	char **name, **kept = offmons.data;
+	Monitor *m;
+
+	wl_array_for_each(name, &offmons) {
+		wl_list_for_each(m, &mons, link)
+			if (!strcmp(*name, m->wlr_output->name))
+				break;
+		if (&m->link != &mons)
+			*kept++ = *name;
+		else
+			free(*name);
+	}
+	offmons.size = (char *)kept - (char *)offmons.data;
+}
+
 void
 fullscreennotify(struct wl_listener *listener, void *data)
 {
@@ -2272,8 +2342,12 @@ outputmgrapplyortest(struct wlr_output_configuration_v1 *config, int test)
 	for (i = 0; i < states_len; i++) {
 		struct wlr_swapchain *swapchain = wlr_output_swapchain_manager_get_swapchain(
 				&swapchain_manager, states[i].output);
-		if (swapchain && !states[i].output->enabled)
-			wlr_output_state_set_buffer(&states[i].base, wlr_swapchain_acquire(swapchain));
+		struct wlr_buffer *buffer;
+		if (swapchain && !states[i].output->enabled
+				&& (buffer = wlr_swapchain_acquire(swapchain))) {
+			wlr_output_state_set_buffer(&states[i].base, buffer);
+			wlr_buffer_unlock(buffer);
+		}
 	}
 
 	if (!(ok = wlr_backend_commit(backend, states, states_len)))
@@ -2405,6 +2479,8 @@ powermgrsetmode(struct wl_listener *listener, void *data)
 	if (!m)
 		return;
 
+	if (event->mode)
+		forgetoffmons();
 	m->gamma_lut_changed = 1; /* Reapply gamma LUT when re-enabling the output */
 	wlr_output_state_set_enabled(&state, event->mode);
 	/* The output was reconnected while off and was never modeset */
@@ -2749,6 +2825,7 @@ setup(void)
 	 * if an X11 server is running. */
 	if (!(backend = wlr_backend_autocreate(event_loop, &session)))
 		die("couldn't create backend");
+	wl_signal_add(&backend->events.destroy, &backend_destroy);
 
 	/* Initialize the scene graph used to lay out windows */
 	scene = wlr_scene_create();
@@ -3142,7 +3219,7 @@ void
 transactionapply(void)
 {
 	struct wlr_scene_node **ghost;
-	Client *c;
+	Client *c, *p;
 	Monitor *m;
 
 	wl_event_source_timer_update(transaction_timer, 0);
@@ -3164,7 +3241,8 @@ transactionapply(void)
 	wl_list_for_each(m, &mons, link) {
 		if (m->wlr_output->enabled)
 			wlr_scene_node_set_enabled(&m->fullscreen_bg->node,
-					(c = focustop(m)) && c->isfullscreen);
+					(c = focustop(m)) && (c->isfullscreen
+					|| ((p = client_get_parent(c)) && p->isfullscreen)));
 	}
 
 	motionnotify(0, NULL, 0, 0, 0, 0);