You shouldn't change any settings in the Edit .htaccess window if your URLs rewriting works correctly or unless you know what you're doing.
The check box is OK, it just doesn't do anything because there are no 301 redirects set.
But I've tested the Aliases feature and found out that you can use it to redirect the homepage too, there's just some bug not displaying it correctly. So just set the Alias list as:
and save the URL. The redirect for homepage should work, but when you open the URL again, the "/" alias will not be displayed in the list because of the bug. Be careful not to save the URL again with "/" alias missing.