Steps to reproduce:

1. Open map constructor.
2. Get map element editing popup opened.
3. Pick any type except "image".
4. Press "Select" for multiselect field for selected type of resource.
5. Once the popup is opened, press Escape on your keyboard.

Result:
Both multiselect popup and element editing popups are closed and all changes you have made are lost.

Expected:
In 6.0 and 6.4, editing popup cannot be closed using keyboard "Escape". I think this was much better although also was inconsistent with other popups in frontend.

There is necessary a decision how this have to be fixed. I would expect a confirmation dialog when element editing popup gets closed but this is not common in Zabbix.