Steps to reproduce:

1. Create a Zabbix Composed Server
   using "docker-compose_v3_alpine_mysql_latest.yaml"
2. No configuration file edits (default settings).
3. Log into Zabbix
4. Set "zabbix-docker-zabbix-agent-1" as zabbix server dns name
5. Access Monitoring - Maps
6. Edit the "Local network" map
7. Add a rectangle shape, add a line shape
8. Comment: The lines and shapes are visible in the edit area.
9. Comment: This also affects link lines.
10. Save
11. View in Maps, this will show no lines, rectangles, or links.
12. Also adding the Map as a widget to the dashboard does not show the lines, rectangles. or links.

I'm adding screenshots from 7.0.8 and 7.2.2 using the same method to install zabbix.
The arrangement of the elements is a little different as I created it from scratch, but the affect is not changed.

Result:
See screenshot:

1. Monitoring-Maps-Edit.png
2. Dashboard-Widget_7.2.2.png

Expected:
See screenshot:

1. Dashboard-Widget_7.0.8.png