Work on Asp.net vs2008 C#.My project have one master page . My master page contain three parts,Like as bellow picture.Clicking on menu item,page show on part 3,I can do that. But I want clicking on menu ,just update the part 3 not 1 and 2.My present scenario is that ,click on menu item-3 post back whole page and menu control become reset.so after postback i can not get the selected menu item.I want after postback only my master page body update but not the menu control.

If have any query plz ask.
It is possible to organize the required layout with the use of the DevExpress ASPxSplitter (with set of SpitterPanes) and ASPxMenu / ASPxNavBars control:
http://demos.devexpress.com/ASPxperienceDemos/Splitter/ContentUrl.aspx
http://demos.devexpress.com/ASPxperienceDemos/Splitter/FullscreenMode.aspx