Hi, 

First... it's really hard to work with the sample you attached here, because it's blowing up with Exceptions all over the place. This is because you have some type mismatches between the ValueMember in your dropdown and the actual DataType of the grid cell. And also because your InitializeLayout code is getting hit more than once you are trying to create Appearance objects that already exist with the same key. 

In ant case, what's happening here is that since you are using groups and levels, each level within the row has the same height. So the height is divided evenly between the two levels. So since the Description column is Multiline, the Identifier column ends up with the same height, even though it doesn't need that much room. 

There's no way around that with Groups and Levels. That's just a limitation of that RowLayoutStyle. 

But you could use RowLayoutStyle.ColumnLayout, instead. It's a bit more complex to set up, but it will distribute the space more efficiently. The code to do that looks something like this: 

            //// In order to make the description appear below the name, we need to use groups and 
            //// levels. This create two levels for each row of data. 
            //band.GroupHeadersVisible = false;
            //if (band.Groups.Count == 0)
            //{
            //    var group = band.Groups.Add("Group 0");
            //    nameColumn.Group = group;
            //    descriptionColumn.Group = group;
            //    band.LevelCount = 2;
            //    descriptionColumn.Level = 1;
            //}
            band.RowLayoutStyle = RowLayoutStyle.ColumnLayout;
            nameColumn.RowLayoutColumnInfo.OriginX = 0;
            nameColumn.RowLayoutColumnInfo.OriginY = 0;
            nameColumn.RowLayoutColumnInfo.SpanX = 2;
            nameColumn.RowLayoutColumnInfo.SpanY = 2;
            descriptionColumn.RowLayoutColumnInfo.OriginX = 0;
            descriptionColumn.RowLayoutColumnInfo.OriginY = 2;
            descriptionColumn.RowLayoutColumnInfo.SpanX = 2;
            descriptionColumn.RowLayoutColumnInfo.SpanY = 2;

Doing this in your sample gets you most of the way there, but there's still an issue because your code is AutoSizing the Description column. So you end up with a very WIDE dropdown. In order to get the description to show up multiline instead of taking up all of the available horizontal space, you need to remove this line of code: 

cboStyledActions.DisplayLayout.PerformAutoResizeColumns(false, PerformAutoSizeType.AllRowsInBand);

What you might want to do instead, is to simply autosize the Idenitifer column to that the width of the dropdown is determine by the longest Identifier and then the Description wraps to multiple lines. 

//cboStyledActions.DisplayLayout.PerformAutoResizeColumns(false, PerformAutoSizeType.AllRowsInBand);
            cboStyledActions.DisplayLayout.Bands[0].Columns["Identifier"].PerformAutoResize(PerformAutoSizeType.AllRowsInBand);