Use onstorage event - don't poll. Increase screenshot frequency to one second.

guacamole/src/main/webapp/scripts/history.js

@@ -132,6 +132,9 @@ GuacamoleHistory = new (function() {
      */
     this.onchange = null;
 
+    // Reload when modified
+    window.addEventListener("storage", guac_history.reload);
+
     // Initial load
     guac_history.reload();