Steps to reproduce:

1. Create 2 hostgroup as 'VirtualMachine' and 'VirtualMachine/Windows'
2. Create a map.
3. add a new map element.
4. Select 'Host Group' as type.
5. Select a parent hostgroup as 'Host Group' ( 'VirtualMachine' in our case) .
6. create a host and put it in our  'VirtualMachine/Windows' group.
7. Generate a problem for our new host.

Result:

1. The map show status 'ok' ( green ) for this element ( host group ).

Expected:
1. Error from members of group 'VirtualMachine/Windows' ( nested host group ) should be visible on map even if hostgroup 'VirtualMachine' was selected for our map element.