@Lynne is right, again!
Because @Lynne pointed this out, I rechecked v4.2.1 and a drop-down menu on the main tab (of course) is included. I was pretty sure they added it, I just did not set it up right in the first place. I added drop-downs to the navigation software on my own system in v4.2.0, so it confused me.
vBulletin v4.2.1 Release Changes
http://www.vbulletin.com/forum/forum...-been-released
It is not obvious in the navigational setup as it is not defined in the attachment drop-down selection box, but in the main setup area, but only after you attach a sub-menu.
Look for this line on the navigational menu - main tab page.
A sub-menu for this tab must be created before this option can be used.
Thanks @Lynne