Welcome to the list. It could be a variety of things but if I was sitting right next to you, I'd ask you if you had clicked 'refresh' to see the new menu as the user. Also, you didn't specify the version of OW that you were running but I'm going to assume that you are running XE since you mentioned Solution Explorer. It's also possible that the user doesn't have security to any of the apps on your menu as we don't know what kind of security you have set up. There really are too many unknowns in your question to give a helpful first answer but this should get you started.
Thanks,
Carrie Ricotta