Sorry for the confusion. Since people are often entering several domain names in our bulk search, we do limit the number of domain extensions you can select to 10. You're right though, it is confusing that we have a "check all" button and we are actually in the process of removing that now. Since you are only looking for one domain name and you want to check several domain extensions, you can use our advanced search and hit "check all." Our advanced search does not have a limit on the number of domain extensions you can select: http://www.dynadot.com/domain/search-advanced.html. We hope that helps!