FrameworkElement.Parent and VisualtreeHelper.GetParent behaves differently

Question

In a WP7 app, I used FrameworkElement.Parent recursively to determine whether a specific element is inside of another element. But it does not always work correctly. Then I

Answer 1

"The value reported by the FrameworkElement.Parent property in Silverlight is generally the same value that would be reported by using VisualTreeHelper API, because the two tree concepts are frequently synchronized as far as how parent-child relationships are reported. However, there may be cases where FrameworkElement.Parent reports a parent that VisualTreeHelper does not."

http://msdn.microsoft.com/en-us/library/system.windows.frameworkelement.parent(v=VS.95).aspx