diff --git a/format.c b/format.c
index 1f6b58e7..31fba2a9 100644
--- a/format.c
+++ b/format.c
@@ -4464,7 +4464,9 @@ format_loop_sessions(struct format_expand_state *es, const char *fmt)
 	for (i = 0; i < n; i++) {
 		s = l[i];
 		format_log(es, "session loop: $%u", s->id);
-		if (active != NULL && s->id == ft->c->session->id)
+		if (active != NULL &&
+		    ft->c != NULL &&
+		    s->id == ft->c->session->id)
 			use = active;
 		else
 			use = all;
diff --git a/screen-write.c b/screen-write.c
index 324ad7d2..da4068c0 100644
--- a/screen-write.c
+++ b/screen-write.c
@@ -2437,8 +2437,10 @@ screen_write_alternateon(struct screen_write_ctx *ctx, struct grid_cell *gc,
 	screen_write_collect_flush(ctx, 0, __func__);
 	screen_alternate_on(ctx->s, gc, cursor);
 
-	if (wp != NULL)
+	if (wp != NULL) {
 		layout_fix_panes(wp->window, NULL);
+		server_redraw_window_borders(wp->window);
+	}
 
 	screen_write_initctx(ctx, &ttyctx, 1);
 	if (ttyctx.redraw_cb != NULL)
@@ -2459,8 +2461,10 @@ screen_write_alternateoff(struct screen_write_ctx *ctx, struct grid_cell *gc,
 	screen_write_collect_flush(ctx, 0, __func__);
 	screen_alternate_off(ctx->s, gc, cursor);
 
-	if (wp != NULL)
+	if (wp != NULL) {
 		layout_fix_panes(wp->window, NULL);
+		server_redraw_window_borders(wp->window);
+	}
 
 	screen_write_initctx(ctx, &ttyctx, 1);
 	if (ttyctx.redraw_cb != NULL)