Hello Paul,

I can see the issue now. You could narrow it even more by checking if the item is a 'HeaderBase' and add one more else - something like this:

 if (e.RowLayoutItem is UltraGridColumn)
            {
                // If the RowLayoutItem is an instance of UltraGridColumn, then cells associated
                // with that column are being resized.
                UltraGridColumn column = (UltraGridColumn)e.RowLayoutItem;

                Debug.Write("Cell in row-layout resized. Column = " + column.Header.Caption);
            }
            else if (e.RowLayoutItem is HeaderBase)
            {
                // If the RowLayoutItem is an instance of HeaderBase, then column header (also 
                // referred to as column label) is being resized.
                HeaderBase header = (HeaderBase)e.RowLayoutItem;

                Debug.Write("Header in row-layout resized. Header = " + header.Caption);
            }
            else
            {
                // if the item is a CellLayoutItem..............
                //
            }

Please let me know if I misunderstood you requirement, I will be glad to assist you further.

Hi Boris,

I can see your example working. It has allowed me to narrow the problem down to the UltraGridGroups I create during InitializeLayout which are causing the problem.

However I can not see how they are causing the problem. I have attached a sample which demonstrates the problem.

Once again any help is greatly appreciated.

Many Thanks
Paul 

Hi,

My bad. It is attached to the above post now.

Hi Boris,

I can't see the attached application?

Hello,

I tried this code in my sample and was not able to reproduce the null exception. I attached the application I am using to this post for you. Please review it and feel free to let me know if I misunderstood you or if you have any other questions.