diff --git a/src/dispatch/bind_define.h b/src/dispatch/bind_define.h
index 36bf199..f3adb81 100644
--- a/src/dispatch/bind_define.h
+++ b/src/dispatch/bind_define.h
@@ -1,5 +1,6 @@
 int32_t bind_to_view(const Arg *arg) {
-
+	if (!selmon)
+		return 0;
 	uint32_t target = arg->ui;
 
 	if (view_current_to_back && selmon->pertag->curtag &&
@@ -101,6 +102,8 @@ int32_t defaultgaps(const Arg *arg) {
 }
 
 int32_t exchange_client(const Arg *arg) {
+	if (!selmon)
+		return 0;
 	Client *c = selmon->sel;
 	if (!c || c->isfloating)
 		return 0;
@@ -113,6 +116,9 @@ int32_t exchange_client(const Arg *arg) {
 }
 
 int32_t exchange_stack_client(const Arg *arg) {
+	if (!selmon)
+		return 0;
+
 	Client *c = selmon->sel;
 	Client *tc = NULL;
 	if (!c || c->isfloating || c->isfullscreen || c->ismaximizescreen)
@@ -266,42 +272,56 @@ int32_t incnmaster(const Arg *arg) {
 }
 
 int32_t incgaps(const Arg *arg) {
+	if (!selmon)
+		return 0;
 	setgaps(selmon->gappoh + arg->i, selmon->gappov + arg->i,
 			selmon->gappih + arg->i, selmon->gappiv + arg->i);
 	return 0;
 }
 
 int32_t incigaps(const Arg *arg) {
+	if (!selmon)
+		return 0;
 	setgaps(selmon->gappoh, selmon->gappov, selmon->gappih + arg->i,
 			selmon->gappiv + arg->i);
 	return 0;
 }
 
 int32_t incogaps(const Arg *arg) {
+	if (!selmon)
+		return 0;
 	setgaps(selmon->gappoh + arg->i, selmon->gappov + arg->i, selmon->gappih,
 			selmon->gappiv);
 	return 0;
 }
 
 int32_t incihgaps(const Arg *arg) {
+	if (!selmon)
+		return 0;
 	setgaps(selmon->gappoh, selmon->gappov, selmon->gappih + arg->i,
 			selmon->gappiv);
 	return 0;
 }
 
 int32_t incivgaps(const Arg *arg) {
+	if (!selmon)
+		return 0;
 	setgaps(selmon->gappoh, selmon->gappov, selmon->gappih,
 			selmon->gappiv + arg->i);
 	return 0;
 }
 
 int32_t incohgaps(const Arg *arg) {
+	if (!selmon)
+		return 0;
 	setgaps(selmon->gappoh + arg->i, selmon->gappov, selmon->gappih,
 			selmon->gappiv);
 	return 0;
 }
 
 int32_t incovgaps(const Arg *arg) {
+	if (!selmon)
+		return 0;
 	setgaps(selmon->gappoh, selmon->gappov + arg->i, selmon->gappih,
 			selmon->gappiv);
 	return 0;
@@ -331,6 +351,8 @@ int32_t setmfact(const Arg *arg) {
 
 int32_t killclient(const Arg *arg) {
 	Client *c = NULL;
+	if (!selmon)
+		return 0;
 	c = selmon->sel;
 	if (c) {
 		pending_kill_client(c);
@@ -400,6 +422,8 @@ int32_t moveresize(const Arg *arg) {
 
 int32_t movewin(const Arg *arg) {
 	Client *c = NULL;
+	if (!selmon)
+		return 0;
 	c = selmon->sel;
 	if (!c || c->isfullscreen)
 		return 0;
@@ -443,6 +467,8 @@ int32_t quit(const Arg *arg) {
 
 int32_t resizewin(const Arg *arg) {
 	Client *c = NULL;
+	if (!selmon)
+		return 0;
 	c = selmon->sel;
 	int32_t offsetx = 0, offsety = 0;
 
@@ -547,6 +573,8 @@ int32_t restore_minimized(const Arg *arg) {
 
 int32_t setlayout(const Arg *arg) {
 	int32_t jk;
+	if (!selmon)
+		return 0;
 
 	for (jk = 0; jk < LENGTH(layouts); jk++) {
 		if (strcmp(layouts[jk].name, arg->v) == 0) {
@@ -572,6 +600,8 @@ int32_t setkeymode(const Arg *arg) {
 }
 
 int32_t set_proportion(const Arg *arg) {
+	if (!selmon)
+		return 0;
 
 	if (selmon->isoverview || !is_scroller_layout(selmon))
 		return 0;
@@ -597,6 +627,8 @@ int32_t smartmovewin(const Arg *arg) {
 	Client *c = NULL, *tc = NULL;
 	int32_t nx, ny;
 	int32_t buttom, top, left, right, tar;
+	if (!selmon)
+		return 0;
 	c = selmon->sel;
 	if (!c || c->isfullscreen)
 		return 0;
@@ -698,6 +730,8 @@ int32_t smartresizewin(const Arg *arg) {
 	Client *c = NULL, *tc = NULL;
 	int32_t nw, nh;
 	int32_t buttom, top, left, right, tar;
+	if (!selmon)
+		return 0;
 	c = selmon->sel;
 	if (!c || c->isfullscreen)
 		return 0;
@@ -766,6 +800,8 @@ int32_t smartresizewin(const Arg *arg) {
 
 int32_t centerwin(const Arg *arg) {
 	Client *c = NULL;
+	if (!selmon)
+		return 0;
 	c = selmon->sel;
 
 	if (!c || c->isfullscreen || c->ismaximizescreen)
@@ -946,6 +982,9 @@ int32_t switch_layout(const Arg *arg) {
 	uint32_t target_tag = selmon->pertag->curtag ? selmon->pertag->curtag
 												 : selmon->pertag->prevtag;
 
+	if (!selmon)
+		return 0;
+
 	if (config.circle_layout_count != 0) {
 		for (jk = 0; jk < config.circle_layout_count; jk++) {
 
@@ -995,6 +1034,8 @@ int32_t switch_layout(const Arg *arg) {
 
 int32_t switch_proportion_preset(const Arg *arg) {
 	float target_proportion = 0;
+	if (!selmon)
+		return 0;
 
 	if (config.scroller_proportion_preset_count == 0) {
 		return 0;
@@ -1039,6 +1080,8 @@ int32_t switch_proportion_preset(const Arg *arg) {
 }
 
 int32_t tag(const Arg *arg) {
+	if (!selmon)
+		return 0;
 	Client *target_client = selmon->sel;
 	tag_client(arg, target_client);
 	return 0;
@@ -1046,6 +1089,8 @@ int32_t tag(const Arg *arg) {
 
 int32_t tagmon(const Arg *arg) {
 	Monitor *m = NULL, *cm = NULL;
+	if (!selmon)
+		return 0;
 	Client *c = focustop(selmon);
 
 	if (!c)
@@ -1137,6 +1182,9 @@ int32_t tagsilent(const Arg *arg) {
 }
 
 int32_t tagtoleft(const Arg *arg) {
+	if (!selmon)
+		return 0;
+
 	if (selmon->sel != NULL &&
 		__builtin_popcount(selmon->tagset[selmon->seltags] & TAGMASK) == 1 &&
 		selmon->tagset[selmon->seltags] > 1) {
@@ -1146,6 +1194,9 @@ int32_t tagtoleft(const Arg *arg) {
 }
 
 int32_t tagtoright(const Arg *arg) {
+	if (!selmon)
+		return 0;
+
 	if (selmon->sel != NULL &&
 		__builtin_popcount(selmon->tagset[selmon->seltags] & TAGMASK) == 1 &&
 		selmon->tagset[selmon->seltags] & (TAGMASK >> 1)) {
@@ -1174,6 +1225,8 @@ int32_t toggle_named_scratchpad(const Arg *arg) {
 }
 
 int32_t toggle_render_border(const Arg *arg) {
+	if (!selmon)
+		return 0;
 	render_border = !render_border;
 	arrange(selmon, false, false);
 	return 0;
@@ -1209,6 +1262,8 @@ int32_t toggle_scratchpad(const Arg *arg) {
 }
 
 int32_t togglefakefullscreen(const Arg *arg) {
+	if (!selmon)
+		return 0;
 	Client *sel = focustop(selmon);
 	if (sel)
 		setfakefullscreen(sel, !sel->isfakefullscreen);
@@ -1216,6 +1271,9 @@ int32_t togglefakefullscreen(const Arg *arg) {
 }
 
 int32_t togglefloating(const Arg *arg) {
+	if (!selmon)
+		return 0;
+
 	Client *sel = focustop(selmon);
 
 	if (selmon && selmon->isoverview)
@@ -1237,6 +1295,9 @@ int32_t togglefloating(const Arg *arg) {
 }
 
 int32_t togglefullscreen(const Arg *arg) {
+	if (!selmon)
+		return 0;
+
 	Client *sel = focustop(selmon);
 	if (!sel)
 		return 0;
@@ -1253,6 +1314,9 @@ int32_t togglefullscreen(const Arg *arg) {
 }
 
 int32_t toggleglobal(const Arg *arg) {
+	if (!selmon)
+		return 0;
+
 	if (!selmon->sel)
 		return 0;
 	if (selmon->sel->is_in_scratchpad) {
@@ -1271,12 +1335,18 @@ int32_t toggleglobal(const Arg *arg) {
 }
 
 int32_t togglegaps(const Arg *arg) {
+	if (!selmon)
+		return 0;
+
 	enablegaps ^= 1;
 	arrange(selmon, false, false);
 	return 0;
 }
 
 int32_t togglemaximizescreen(const Arg *arg) {
+	if (!selmon)
+		return 0;
+
 	Client *sel = focustop(selmon);
 	if (!sel)
 		return 0;
@@ -1295,6 +1365,9 @@ int32_t togglemaximizescreen(const Arg *arg) {
 }
 
 int32_t toggleoverlay(const Arg *arg) {
+	if (!selmon)
+		return 0;
+
 	if (!selmon->sel || !selmon->sel->mon || selmon->sel->isfullscreen) {
 		return 0;
 	}
@@ -1316,6 +1389,9 @@ int32_t toggleoverlay(const Arg *arg) {
 }
 
 int32_t toggletag(const Arg *arg) {
+	if (!selmon)
+		return 0;
+
 	uint32_t newtags;
 	Client *sel = focustop(selmon);
 	if (!sel)
@@ -1339,13 +1415,15 @@ int32_t toggletag(const Arg *arg) {
 }
 
 int32_t toggleview(const Arg *arg) {
+	if (!selmon)
+		return 0;
+
 	uint32_t newtagset;
 	uint32_t target;
 
 	target = arg->ui == 0 ? ~0 & TAGMASK : arg->ui;
 
-	newtagset =
-		selmon ? selmon->tagset[selmon->seltags] ^ (target & TAGMASK) : 0;
+	newtagset = selmon->tagset[selmon->seltags] ^ (target & TAGMASK);
 
 	if (newtagset) {
 		selmon->tagset[selmon->seltags] = newtagset;
@@ -1357,6 +1435,9 @@ int32_t toggleview(const Arg *arg) {
 }
 
 int32_t viewtoleft(const Arg *arg) {
+	if (!selmon)
+		return 0;
+
 	uint32_t target = selmon->tagset[selmon->seltags];
 
 	if (selmon->isoverview || selmon->pertag->curtag == 0) {
@@ -1377,6 +1458,9 @@ int32_t viewtoleft(const Arg *arg) {
 }
 
 int32_t viewtoright(const Arg *arg) {
+	if (!selmon)
+		return 0;
+
 	if (selmon->isoverview || selmon->pertag->curtag == 0) {
 		return 0;
 	}
@@ -1394,6 +1478,9 @@ int32_t viewtoright(const Arg *arg) {
 }
 
 int32_t viewtoleft_have_client(const Arg *arg) {
+	if (!selmon)
+		return 0;
+
 	uint32_t n;
 	uint32_t current = get_tags_first_tag_num(selmon->tagset[selmon->seltags]);
 	bool found = false;
@@ -1418,6 +1505,9 @@ int32_t viewtoleft_have_client(const Arg *arg) {
 }
 
 int32_t viewtoright_have_client(const Arg *arg) {
+	if (!selmon)
+		return 0;
+
 	uint32_t n;
 	uint32_t current = get_tags_first_tag_num(selmon->tagset[selmon->seltags]);
 	bool found = false;
@@ -1442,6 +1532,9 @@ int32_t viewtoright_have_client(const Arg *arg) {
 }
 
 int32_t viewcrossmon(const Arg *arg) {
+	if (!selmon)
+		return 0;
+
 	focusmon(&(Arg){.v = arg->v, .i = UNDIR});
 	view_in_mon(arg, true, selmon, true);
 	return 0;
@@ -1520,6 +1613,8 @@ int32_t setoption(const Arg *arg) {
 }
 
 int32_t minimized(const Arg *arg) {
+	if (!selmon)
+		return 0;
 
 	if (selmon && selmon->isoverview)
 		return 0;
@@ -1542,6 +1637,8 @@ void fix_mon_tagset_from_overview(Monitor *m) {
 
 int32_t toggleoverview(const Arg *arg) {
 	Client *c = NULL;
+	if (!selmon)
+		return 0;
 
 	if (selmon->isoverview && ov_tab_mode && arg->i != 1 && selmon->sel) {
 		focusstack(&(Arg){.i = 1});
@@ -1647,6 +1744,8 @@ int32_t toggle_monitor(const Arg *arg) {
 }
 
 int32_t scroller_stack(const Arg *arg) {
+	if (!selmon)
+		return 0;
 	Client *c = selmon->sel;
 	Client *stack_head = NULL;
 	Client *source_stack_head = NULL;
diff --git a/src/fetch/client.h b/src/fetch/client.h
index 8fccb26..11edb76 100644
--- a/src/fetch/client.h
+++ b/src/fetch/client.h
@@ -83,6 +83,9 @@ setclient_coordinate_center(Client *c, Monitor *tm, struct wlr_box geom,
 	int32_t len = 0;
 	Monitor *m = tm ? tm : selmon;
 
+	if (!m)
+		return geom;
+
 	uint32_t cbw = check_hit_no_border(c) ? c->bw : 0;
 
 	if (!c->no_force_center && m) {
diff --git a/src/mango.c b/src/mango.c
index ce173ad..b4acfe0 100644
--- a/src/mango.c
+++ b/src/mango.c
@@ -1401,6 +1401,9 @@ void applyrules(Client *c) {
 	Client *fc = NULL;
 	Client *parent = NULL;
 
+	if (!c)
+		return;
+
 	parent = client_get_parent(c);
 
 	Monitor *mon = parent && parent->mon ? parent->mon : selmon;
@@ -1489,7 +1492,8 @@ void applyrules(Client *c) {
 	/*-----------------------apply rule action-------------------------*/
 
 	// rule action only apply after map not apply in the init commit
-	if (!client_surface(c)->mapped)
+	struct wlr_surface *surface = client_surface(c);
+	if (!surface || !surface->mapped)
 		return;
 
 	// apply swallow rule
@@ -1515,6 +1519,7 @@ void applyrules(Client *c) {
 	setmon(c, mon, newtags,
 		   !c->isopensilent &&
 			   !(client_is_x11_popup(c) && client_should_ignore_focus(c)) &&
+			   mon &&
 			   (!c->istagsilent || !newtags ||
 				newtags & mon->tagset[mon->seltags]));
 
@@ -1536,7 +1541,7 @@ void applyrules(Client *c) {
 	window in the current tag will exit fullscreen and participate in tiling
 	*/
 	wl_list_for_each(fc, &clients,
-					 link) if (fc && fc != c && c->tags & fc->tags &&
+					 link) if (fc && fc != c && c->tags & fc->tags && c->mon &&
 							   VISIBLEON(fc, c->mon) && ISFULLSCREEN(fc) &&
 							   !c->isfloating) {
 		clear_fullscreen_flag(fc);
@@ -1555,7 +1560,7 @@ void applyrules(Client *c) {
 	}
 
 	// apply overlay rule
-	if (c->isoverlay) {
+	if (c->isoverlay && c->scene) {
 		wlr_scene_node_reparent(&c->scene->node, layers[LyrOverlay]);
 		wlr_scene_node_raise_to_top(&c->scene->node);
 	}