diff --git a/window.c b/window.c
index 19e0ab51..af2ccac4 100644
--- a/window.c
+++ b/window.c
@@ -1244,7 +1244,7 @@ window_pane_set_mode(struct window_pane *wp, struct window_pane *swp,
 		TAILQ_INSERT_HEAD(&wp->modes, wme, entry);
 		wme->screen = wme->mode->init(wme, fs, args);
 	}
-	wme->kill = args_has(args, 'k');
+	wme->kill = args != NULL ? args_has(args, 'k') : 0;
 	wp->screen = wme->screen;
 
 	wp->flags |= (PANE_REDRAW|PANE_REDRAWSCROLLBAR|PANE_CHANGED);