Steps to reproduce:

1. In a fresh Zabbix instance add another host with geo coordinates.
2. Go to the Global view dashboard.
3. Edit the Geomap widget, clear the "Hosts" field and press Apply.
4. Now there should be two hosts in the Geomap - Zabbix server and the one you added.
5. Without saving the widget click and drag the map.

Result:
Browser console error:

TypeError: Cannot read properties of undefined (reading 'classList')

Demo: