diff --git a/public/monitor.js b/public/monitor.js
index 57b4cbe..b98b62a 100644
--- a/public/monitor.js
+++ b/public/monitor.js
@@ -184,7 +184,7 @@ function setup_ws() {
       },
     }) => {
       if (action === "monitor" && Array.isArray(args.targets)) {
-        monitored = args.targets
+        monitored = args.targets.filter(Boolean)
         redraw_clients(clients, monitored)
       } else if (action === "text" && args.text !== undefined) {
         if (args.text.length) {