It is recommended to create the RadDockZone on the Init
page event and to always setup it with the same ID
in order to ensure that the RadDock state will be stored correctly. Please use this approach for dynamically adding the dock zone controls if you have not done so already.
Also, you mentioned that you inserted a PlaceHolder inside the RadDockZone. Since the RadDockZone accepts as content only RadDock controls you probably meant another setup. Please elaborate on your implementation so that I can help you accordingly.
If you are still having difficulties, please open a support ticket
and send a simple, runnable page
that isolates your problem so that I can examine it locally and provide a working solution.
All the best,
the Telerik team
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