StyleManager.ApplicationTheme = new CrystalTheme();

<telerik:RadDocking Grid.Row="2" telerik:StyleManager.Theme="Office2016">
	<telerik:RadDocking.DocumentHost >
		<telerik:RadSplitContainer>
			<telerik:RadPaneGroup>
				<telerik:RadPane Header="Description">
					<TextBlock TextWrapping="Wrap" Text="On the Documents tab above press Ctrl + Mouse Left button to display the Popup Menu. You can use the same combination on every tab."/>
				</telerik:RadPane>
			</telerik:RadPaneGroup>
		</telerik:RadSplitContainer>
	</telerik:RadDocking.DocumentHost>
	<telerik:RadSplitContainer InitialPosition="DockedBottom">
		<telerik:RadPaneGroup>
			<telerik:RadPane Header="NonDraggable">
				<TextBlock TextWrapping="Wrap" Text="This pane cannot be dragged, because it has its property CanFloat set 'False'."/>
			</telerik:RadPane>
		</telerik:RadPaneGroup>
	</telerik:RadSplitContainer>
</telerik:RadDocking>

private void RadDocking_ToolWindowCreated(object sender, Telerik.Windows.Controls.Docking.ElementCreatedEventArgs e)
{
    var window = (ToolWindow)e.CreatedElement;
    window.IsTopmost = false;
}

   private void RadDocking_LayoutChangeEnded(object? sender, EventArgs e)
    {
        var docking = (RadDocking)sender;
        if (docking.ActivePane != null && !docking.Panes.OfType<RadPane>().Contains(docking.ActivePane))
        {
            docking.ActivePane = null;
        }
    }