Grafana: Datasource connected, but not "metrics" in the chart settings?

I installed InfluxDB & Grafana according to the tutorial in this forum, added the database & the users and I was also able to add the data source & add a dashboard. But when I add a chart in the Grafana GUI, there is no “metrics” tab where I can choose a data source (db, table, whatever) to be displayed - the tab is simply missing.

What did I miss?

Never mind, found it - you need to click on the title