You can use the e.OriginalSource property in combination with the ParentOfType extension method to get the target PropertyGridField.
var field = e.OriginalSource as PropertyGridField ?? (e.OriginalSource as FrameworkElement).ParentOfType<
Hope this helps.
Check out Telerik Analytics, the service which allows developers to discover app usage patterns, analyze user data, log exceptions, solve problems and profile application performance at run time. Watch the videos
and start improving your app based on facts, not hunches.