Hi Jason,

If you want to keep the group header in view at all times, then you'd have to use a CreationFilter. There's no property setting for this.

If you have not worked with CreationFilters before, they can be a bit daunting, but they are well worth the effort they take to learn because they are so powerful.

This one is a bit tricky. What you have to do is make sure the TextUIElement that is inside the HeaderUIElement for the group doesn't span the entire width of the HeaderUIElement (which gets scrolled off-screen), but is instead limited by the visible area of the grid. And you would have to do this for both the left and the right.

And just to make this even more complicated, you would have to refresh the elements any time the grid scrolls.

Here's some quick sample code I whipped up which seems to work okay, although I didn't test it very thoroughly:

    public class MyCreationFilter : IUIElementCreationFilter
    {
        #region IUIElementCreationFilter Members

        void IUIElementCreationFilter.AfterCreateChildElements(UIElement parent)
        {
            HeaderUIElement headerUIElement = parent as HeaderUIElement;

            if (headerUIElement != null &&
                headerUIElement.Header != null &&
                headerUIElement.Header.Group != null)
            {
                UIElement textUIElement = parent.GetDescendant(typeof(TextUIElement));
                UIElement rowColRegionIntersectionUIElement = parent.GetAncestor(typeof(RowColRegionIntersectionUIElement));
                if (textUIElement != null &&
                    rowColRegionIntersectionUIElement != null)
                {
                    int newLeft = rowColRegionIntersectionUIElement.Rect.Left;
                    if (newLeft > textUIElement.Rect.Left)
                    {
                        int newWidth = textUIElement.Rect.Width - (newLeft - textUIElement.Rect.Left);
                        textUIElement.Rect = new Rectangle(
                            newLeft,
                            textUIElement.Rect.Top,
                            newWidth,
                            textUIElement.Rect.Height);

                        textUIElement.Invalidate();
                    }
                    else
                    {
                        int newRight = rowColRegionIntersectionUIElement.Rect.Right;
                        if (newRight < textUIElement.Rect.Right)
                        {
                            int newWidth = textUIElement.Rect.Width - (textUIElement.Rect.Right - newRight);
                            textUIElement.Rect = new Rectangle(
                                textUIElement.Rect.Left,
                                textUIElement.Rect.Top,
                                newWidth,
                                textUIElement.Rect.Height);

                            textUIElement.Invalidate();
                        }
                    }
                }
            }
        }

        bool IUIElementCreationFilter.BeforeCreateChildElements(UIElement parent)
        {
            // Do nothing
            return false;
        }

        #endregion
    }