Thank you for writing.
You cannot control both dimensions (width and high) together of RadDocumentWindow independently from the size of RadDock. By design RadDock arranges windows according their DockState and ignores their set size if they are not in split panel with windows from same type. So RadDock
manages the size of the docked RadDocumentWindow and there is not suitable way to change that behavior.
Attached demo demonstrates several possible scenarios with partial success because you can control only one dimension - width or high
You can find more information in the following online article : http://www.telerik.com/help/winforms/dock-object-model-example-building-an-advanced-layout-at-runtime.html
I hope this information helps.
the Telerik team