Fixed Layout

You can use RadSplitter to create several non-resizable regions. To do this, simply add RadPane controls to the splitter without any RadSplitBar controls between them:

The borders of the panes can be removed by setting the PanesBorderSize property to 0.

The layout above was produced by the following declaration:

<telerik:RadSplitter RenderMode="Lightweight" runat="server" id="RadSplitter1"
   Orientation="Vertical" width="600px" height="400px">
 <telerik:RadPane runat="server" id="LeftPane" Width="200px">
   Left pane
 </telerik:RadPane>
 <telerik:RadPane runat="server" id="RightPane" Width="400px">
   <telerik:RadSplitter RenderMode="Lightweight" runat="server" id="RadSplitter2"
       Orientation="Horizontal">
     <telerik:RadPane runat="server" id="TopPane">
       Top Pane
     </telerik:RadPane>
     <telerik:RadPane runat="server" id="BottomPane">
       <telerik:RadSplitter RenderMode="Lightweight" runat="server"
           Orientation="Vertical" Width="400px">
         <telerik:RadPane runat="server" Width="40%">
           Bottom Left Pane
         </telerik:RadPane>
         <telerik:RadPane runat="server">
           Bottom Right Pane
         </telerik:RadPane>
       </telerik:RadSplitter>
     </telerik:RadPane>
   </telerik:RadSplitter>
 </telerik:RadPane>
</telerik:RadSplitter>          

If you want to make changes to some of the panes at runtime, such as resizing or collapsing them, you can use the client-side API.