AJAX updates
RadSlidingPane, RadPane, and RadSplitBar controls can not be updated directly with an Ajax Manager control.
When you want to update the content of a RadPane (or RadSlidingPane) control, just add an asp:Panel control (or any other container control that runs on the server) inside the pane and update the panel instead the RadPane (or RadSlidingPane).
When you want to change the RadSlidingPane, RadPane or RadSplitBar properties, you can do it with the client-side API or you can update the whole Splitter or RadSlidingZone with the Ajax Manager control or with an Ajax Panel control.