RadSplitter for ASP.NET AJAX Version Q3 2008 released 11/25/2008 (release history)

This pane has EnableResize property set ot false.
The default value of the property is true.

You can dock the pane to see that even when docked the pane is still not resizable.

This pane has EnableDock property set ot false. The default value of the property is true.

You can only resize and close this pane.

This pane has both the EnableDock and EnableResize properties set ot false.
By default values of the both properties is true.

You can only close the pane.