https://documentation.devexpress.com/#WindowsForms/clsDevExpressXtraNavBarNavBarControltopic
https://documentation.devexpress.com/#WindowsForms/CustomDocument1637
The three major View types, mentioned above, are Explorer Bar View, Side Bar View and Navigation Pane View.
Explorer Bar View:一次显示所有的group，可以展开或折叠group
Side Bar View和Navigation Pane View一次只显示单个group的内容，不可折叠group
Side Bar View和Navigation Pane View的区别是:前者是按照group的本来的顺序，进行显示。后者所有的group统一显示在下方，选中某一个group再显示
This view is similar to the side bars found in Microsoft Outlook, prior to version 2003.
Only one group‘s content can be visible at a time.
End-users can click the desired group‘s header to make that group‘s content visible.
Clicking a collapsed group‘s header expands the corresponding group, and collapses the previously expanded group.
These Views do not support skinning paint schemes.
原文：http://www.cnblogs.com/chucklu/p/6068581.html