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