By default, you will find when you select one Hosts menu item, the other menu items in this group will be automatically unselected. This is the feature of 'Could only activate one item in a hosts group'.
When to use this feature?
For example, if you need to switch between Development environment (e.g., 192.168.1.80) and Test environment (e.g., 192.168.1.88), you could:
- Add a new group in iHosts.
- Add 'Development' Hosts node, add record of '192.168.1.80 mydomain.com'
- Add 'Test' Hosts node, add record of '192.168.1.88 mydomain.com'
Then during development you can keep using same domain of 'mydomain.com', and switch between Development and Test environment.
If you don't need this feature, you can also disable it in 'Preferences... > General'.