Persisting State
The state of a RadSplitter automatically persists across postbacks, so you do not need to reconfigure it every time to maintain the same appearance. Even if you change the values of the properties listed below using the client-side API, they will persist across postbacks.
RadPane
The following RadPane properties persist across postbacks:
Width, Height - The size of panes persists, even if they are resized using the mouse or the client-side API
MinWidth, MaxWidth, MinHeight, MaxHeight - The maximum and minimum dimensions of the panes persists, even when changed using the client-side API
Collapsed - The collapsed or expanded state of panes persists, even when collapsed or expanded using the mouse or the client-side API
Locked - The locked status of a pane persists, even when changed using the client-side API
ContentUrl - if a RadPane control was initially configured to display an external page, and you change its ContentUrl property using the client-side API, the new value persists across postbacks.
All of the properties listed above are updated on the server-side object after a postback, so you can save them in a database or other storage medium if needed.
In addition to the properties listed above, by default the scrolled position of a RadPane persists across postbacks. You can disable this feature so that the scroll position is reset after a postback by setting the PersistScrollPosition property to False.
RadSlidingZone
The following RadSlidingZone properties persist across postbacks:
DockedPaneId - If a sliding pane is docked using the control in the title bar or the client-side API, it remains docked after a postback.
ExpandedPaneId - If a sliding pane is expanded when a postback occurs, it remains expanded after a postback.
ClickToOpen - If the ClicktoOpen property is changed using the client-side API, the change persists over a postback.
RadSlidingPane
The following RadSlidingPane properties persist across postbacks:
Width, Height - the size of panes persists, even if they are resized using the mouse or client-side API.
MinWidth,MaxWidth, MinHeight, MaxHeight - The maximum and minimum dimensions of the panes persists, even when changed using the client-side API
Title - The title persists, even when changed using the client-side API.
EnableResize, EnableDock - the ability of the pane to be resized or docked by the user persists, even when changed using the client-side API.