diff --git a/utils.R b/utils.R
index 36f7c42..7d7bc48 100644
--- a/utils.R
+++ b/utils.R
@@ -24,5 +24,6 @@ sma_plot_file <- function(fname, ftype, title_list, legend_list, fun, ...) {
 	if(!is.null(legend_list)) {
 		do.call(legend, legend_list)
 	}
-	dev.off()
+	# hide "null device 1" in garbage
+	garbage <- dev.off()
 }