Hi, years later I know. But I was searching for the answer to this question as well, and I see no one was helpful at all. SO I am writing this to help anyone else who may be stuck as well lol. You can only safely have between 6-8 menu items (not including drop downs) for them to be listed across the top. The length of your names determine whether it is 6 or 8. If it is more than that, it will automatically create a hamburger menu. Hope this helps future people lol.