diff --git a/src/demo/boxdemo.c b/src/demo/boxdemo.c
index e39a78145..9accfe9b1 100644
--- a/src/demo/boxdemo.c
+++ b/src/demo/boxdemo.c
@@ -26,6 +26,10 @@ int box_demo(struct notcurses* nc){
   const int targx = 7;
   const int targy = 7;
   int ytargbase = (ylen - targy) / 2;
+  cell c = CELL_SIMPLE_INITIALIZER(' ');
+  cell_set_bg_default(&c);
+  ncplane_set_default(n, &c);
+  cell_release(n, &c);
   ncplane_set_fg_rgb(n, 180, 40, 180);
   ncplane_set_bg_default(n);
   if(ncplane_putstr_aligned(n, ytargbase++, NCALIGN_CENTER, "┏━━┳━━┓") < 0){