If WPF ContextMenu is used (which doesn't have an Opening event), then it can be used the ContextMenuOpening event of RadPane. For example:

XAML:
<telerik:RadPane Header="Pane1" ContextMenuOpening="OnPane1ContextMenuOpening">
    <TextBlock Text="Sample Content">
        <TextBlock.ContextMenu>
            <ContextMenu>
                <MenuItem Header="Item 1" />
                <MenuItem Header="Item 2" />
            </ContextMenu>
        </TextBlock.ContextMenu>
    </TextBlock>
</telerik:RadPane>

Code behind:
private void OnPane1ContextMenuOpening(object sender, System.Windows.Controls.ContextMenuEventArgs e)
{
    (sender as RadPane).IsActive = true;
}

Regards,
Kalin

Hi,

For such scenarios the recommended approach is to hook to the ContextMenu Opening event and manually active the need Pane in order to keep it open. Please check the following snippet that demonstrates how this can be achieved using RadContextMenu:

private void OnRadContextMenuOpening(object sender, Telerik.Windows.RadRoutedEventArgs e)
{
    var clicked = (sender as RadContextMenu).GetClickedElement<FrameworkElement>();
    var pane = clicked.GetParentPane();
    if (pane != null)
    {
        pane.IsActive = true;
    }
}

Regards,
Kalin