Thanks.  I couldn't use that becaus my child control is a flow panel which has child controls added to it on the fly.  Instead I had to monitor the size change of the flow panel and set the group box size as well as the panel with in it to the size of the flowpanel.  This solution is ugly and has performance issues but I haven't found another way.

No, I don't think I ever got a good answer.

This is what I ended up coding:

...

            var sectionPanel = _sectionPanels[i] = new TableLayoutPanel();

            _pnlMainContent.ClientArea.Controls.Add(sectionPanel);

            sectionPanel.Dock = DockStyle.Fill;

            sectionPanel.GrowStyle = TableLayoutPanelGrowStyle.AddRows;

            sectionPanel.AutoScroll = true;

            //GROUPS

            for (int j = 0; j < sectionChild.NoteDictionaryGroups.Count; j++)

            {

               int rowCount = groupChild.NoteDictionaryQuestions.Count;

               var groupBox = new UltraGroupBox();

               groupBox.Dock = DockStyle.Fill;

               sectionPanel.Controls.Add(groupBox);

               groupBox.Height = 20 + rowCount * 24;

//MAGIC NUMBERS: INSTEAD OF AUTOSIZE SINCE INFRAGISTICS GROUP BOXES DON'T IMPLEMENT THEM!  AND YES I AM YELLING

...

notice the silly comment.  I think I had resentment at the time over this issue.

So anyway, yeah, it's a table layout panel, and I just size the group boxes by this rowcount thing so that their minimum size would be at least big enough for single rows for each control.  Although in this example the group boxes will/can grow to fit the panel.