Cannot delete action operation

Cannot delete action operation.

1. Create action
2. Add remote command operation with "Current host" and "Zabbix server"
3. Add & Save

4. Open the action setting
5. Move to Operation tab
6. click "edit" the existing operation (screenshot1)
7. remove "Current host" from the operation (screenshot2)
8. Update & Save (screenshot3 and 4)

However, "Current host" still there.