Chart label disappears when refreshing the browser

I'm trying to use the chart label for displaying the current values of two lines.
It works but when I refresh the browser the label disappears.

chartlabel

chartconfig

Browsers: Chrome and iPhone Safari

you have to send more data (inc msg.label) to refresh the label. You can use the ui_control node to be notified if client connects or changes tabs so you can trigger a resend.

I also tried using msg.topic (doc example) and of course sending all data but same issue.

Edit:

Ok I've added the ui_control > it works