===================================================================
RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/tmux/tty.c,v
retrieving revision 1.412
retrieving revision 1.413
diff -u -r1.412 -r1.413
--- src/usr.bin/tmux/tty.c	2021/11/29 11:05:28	1.412
+++ src/usr.bin/tmux/tty.c	2021/12/06 10:08:42	1.413
@@ -1,4 +1,4 @@
-/* $OpenBSD: tty.c,v 1.412 2021/11/29 11:05:28 nicm Exp $ */
+/* $OpenBSD: tty.c,v 1.413 2021/12/06 10:08:42 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -937,7 +937,9 @@
 	struct client	*c;
 
 	TAILQ_FOREACH(c, &clients, entry) {
-		if (c->session != NULL && c->session->curw->window == w)
+		if (c->session != NULL &&
+		    c->session->curw != NULL &&
+		    c->session->curw->window == w)
 			tty_update_client_offset(c);
 	}
 }