wpf hit testing

Question

I am facing a problem where I need to decide if the visual object im dealing with, is actually VISUALLY visible to user.

The things I've tried(combined), however my approach is still not completely working.

1) If the Object.IsVisible is false, user can't see the object

2) If I can't Transform it, it's not visible:

                Rect bounds = AssociatedObject.TransformToAncestor(container).TransformBounds(new Rect(0.0, 0.0, AssociatedObject.ActualWidth, AssociatedObject.ActualHeight));
                Rect rect = new Rect(0.0, 0.0, container.ActualWidth, container.ActualHeight);
                if (!rect.Contains(bounds.TopLeft) || !rect.Contains(bounds.BottomRight))
                    return;

This is it. However it does not take care of one case what I'd like to:

If we have something like this:

<Grid>
<Grid Background="Purple" />
<Grid Background="Green" />
</Grid>

My "IS visually visible to user" algorithm indicates that yes, "Purple" grid is visible. This is correct however it does not fit me.

I've finally handcrafted something that would ideally work, but it doesn't. It just wont do the correct thing.

    //last check !!
                        var positionTransform = AssociatedObject.TransformToAncestor(container);
                        var areaPosition = positionTransform.Transform(new Point(0, 0));

                        bool dontcreate = false;
                        VisualTreeHelper.HitTest(AssociatedObject, null, new HitTestResultCallback(
                            delegate(HitTestResult result)
                            {
                                FrameworkElement xs = result.VisualHit as FrameworkElement;
                                if (xs != null)
                            {
                                FrameworkElement cv = VisualHelper.FindChild<FrameworkElement>(AssociatedObject, xs.Name);
                                if (cv == null)
                                {
                                    if (_customPopup != null)
                                    {
                                        ReleasePopupIfNeeded();
                                        dontcreate = true;
                                    }
                                }

                            }
                            return HitTestResultBehavior.Stop;
                        }), new PointHitTestParameters(areaPosition));

                    if (dontcreate)
                        return;

The idea is to, find out cordinates of VisualObject. Then use Z-Order HitTesting to recieve first element that is on the cordinates. And if that object is not VisualObject or PART of VisualObject, it sure sounds like it's not visible to user. I am wondering why im not getting the result im hoping for?

Do you have ideas? Thanks.