diff --git a/mode-tree.c b/mode-tree.c
index 2a6f9a220..59d9e4fa9 100644
--- a/mode-tree.c
+++ b/mode-tree.c
@@ -834,6 +834,11 @@ mode_tree_draw(struct mode_tree_data *mtd)
 	if (mtd->line_size == 0)
 		return;
 
+	w = mtd->width;
+	h = mtd->height;
+	if (w == 0 || h == 0)
+		return;
+
 	memcpy(&gc0, &grid_default_cell, sizeof gc0);
 	memcpy(&gc, &grid_default_cell, sizeof gc);
 	style_apply(&gc, oo, "tree-mode-selection-style", NULL);
@@ -843,9 +848,6 @@ mode_tree_draw(struct mode_tree_data *mtd)
 	dfg = gc.fg;
 	dfg0 = gc0.fg;
 
-	w = mtd->width;
-	h = mtd->height;
-
 	screen_write_start(&ctx, s);
 	screen_write_clearscreen(&ctx, 8);
 	ft = format_create_defaults(NULL, NULL, NULL, NULL, wp);