diff --git a/server-client.c b/server-client.c
index c25c7ca19..8344ae190 100644
--- a/server-client.c
+++ b/server-client.c
@@ -1197,6 +1197,8 @@ server_client_update_theme_colours(struct client *c)
 	format_defaults(ft, c, NULL, NULL, NULL);
 
 	theme = c->theme;
+	if (theme == THEME_UNKNOWN)
+		theme = colour_totheme(c->tty.bg);
 	if (option == 2)
 		theme = THEME_LIGHT;
 	else if (option == 3)
diff --git a/tty-keys.c b/tty-keys.c
index f48fb1b71..209bbeeab 100644
--- a/tty-keys.c
+++ b/tty-keys.c
@@ -751,7 +751,7 @@ tty_keys_next(struct tty *tty)
 	const char		*buf;
 	size_t			 len, size;
 	cc_t			 bspace;
-	int			 delay, expired = 0, n;
+	int			 delay, expired = 0, n, bg = tty->bg;
 	key_code		 key, onlykey;
 	struct mouse_event	 m = { 0 };
 	struct key_event	*event;
@@ -811,11 +811,15 @@ tty_keys_next(struct tty *tty)
 	switch (tty_keys_colours(tty, buf, len, &size, &tty->fg, &tty->bg)) {
 	case 0:		/* yes */
 		key = KEYC_UNKNOWN;
+		if (tty->bg != bg)
+			server_client_update_theme_colours(c);
 		session_theme_changed(c->session);
 		goto complete_key;
 	case -1:	/* no, or not valid */
 		break;
 	case 1:		/* partial */
+		if (tty->bg != bg)
+			server_client_update_theme_colours(c);
 		session_theme_changed(c->session);
 		goto partial_key;
 	}