The StackPanel measures itself with infinity. On the other hand, the RadTreeView has to be limited somehow in order to show its vertical ScrollViewer. You could try setting the MaxHeight
property of the RadTreeView or placing it in Grid`s RowDefinition
with explicit height set. You can also send us a runnable sample that we will investigate faster and provide you with a better suited advice. Thank you for your cooperation in advance.
the Telerik team
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