Consistent Navigation

Understanding WCAG2.0

In a broad sense, it is to describe the global navigation in a certain position, but the nonconformity case that the order of the items in the global navigation should be consistent in the site is "Understanding SC 3.2.3" Note that it is illustrated in.

For example, it is important to have "Skip to main content" skip link and set search field in fixed position.

It does not prohibit global navigation from having a drop-down menu.

Principle Understandable Information and the operation of user interface must be understandable.
Guideline Predictable Make Web pages appear and operate in predictable ways.
Criterion Consistent Navigation
(3.2.3 AA)
The repeated navigation mechanism on multiple webpages in a set of webpages appears in the same order as they are repeated. However, except when the user changes.

URL of Techniques for WCAG 2.0