Top menu missing in web fontend

[grenzlaeufer]

Something wired happened: All of the sudden the menu in the frontend ("Monitoring Inventory Reports...") is missing. I have done no configuration change this morning. The last things I had done was making a stacked graph, creating a few aggregated items, a graph of these and adding it to a screen. Nothing which should ever cause this effect:


The gray bar at the top is the beginning of my bookmarks in the browser.

• OS: CentOS 7.7
• httpd-2.4.6
• zabbix-4.0.22

I also followed the Zabbixweb/httpd error log and the Zabbix-Server-log. I could not find any errors in these logs. I checked the zabbix frontend also in another browser. The Menu is also missing there.

Has anyone encountered this problem before and has a clue of how to solve it?

[grenzlaeufer]

Done. I discovered the full screen mode I had never used before.