Thank you for writing.
This is not supported and you cannot exchange windows between different RadDock instances. We are explicitly checking if the current window belongs to the same instance, this is the desired by design behavior.
Please do not hesitate to contact us with any additional questions or concerns.
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Check out the Windows Forms project converter, which aids the conversion process from standard Windows Forms applications written in C# or VB to Telerik UI for WinForms.For more information check out this blog post
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