The global drop-down menu is the menu that springs from the button with your email address on, top-right.
This menu is the 'topmost' navigation in CaptionHub: it is where you alter your password and preferences, how you return to your dashboard, and will take you to lists of all Projects and activity that are relevant to you. It's where the help is linked from, and where the log-out button is.
For Producers and Superusers, it's where much of the administrative tools of CaptionHub can be found.
It's present on every page of the site.
It is distinct from the project drop-down menu or caption set drop-down menu, which appear next to the title of the object they manipulate, further down the page.