My environment:
- Foreman version 1.1 from the foreman debian repository.
- Ubuntu version 12.04 lts 64bit
- installed on an amazon ec2 medium instance

I was creating a new compute resource with the EC2 provider.

When I tried to load the regions no regions appeared in the combobox after clicking the load region button and no error message appeared.

After looking into firebug I could see that the request returned the following error:

"unitialized constant Foreman::Model::EC2::FOG"

Afterwards I installed the foreman-fog and the foreman-compute packages and restarted foreman with the init script but didn't solve the problem.

Finally after terminating all ruby and apache processes and starting them again I could load the regions.

It would be good to throw an error message that there are missing dependencies (fog, compute) and you have to restart apache to get the region loading running.
Probably not every user will look into the requests.

Irc-user Dominic asked to open a feature/bug request so that it can work in a similar way then libvirt.