Column Resizing and DoDragDrop

I am trying handle a drag out of a GridControl that has GridResizeCellsBehavior.InsideGrid set. I handle the MouseDown event and gather all of the drag information. I call DoDragDrop and the drag starts. This part works ok. The problem is that once I call DoDragDrop I cannot resize the columns by dragging the column edge in the grid. It becomes a data drag, not a column resize drag. How can I detect in the MouseDown event whether I am on the column edge or in the middle of the cell? Thanks

Here is one try at it that gets the cell rectangle, and shrinks it a little, and then tests whether the point is in the shrunken rect.

private void gridControl1_MouseDown(object sender, MouseEventArgs e)
{
	int row, col;
	Point pt = new Point(e.X, e.Y);
	if(this.gridControl1.PointToRowCol(pt, out row, out col, -1))
	{
		Rectangle rect = this.gridControl1.ViewLayout.RangeInfoToRectangle(GridRangeInfo.Cell(row, col),
			             true, GridCellSizeKind.ActualSize);
		rect.Inflate(-3, -3);
		if(rect.Contains(pt))
		{
			Console.WriteLine("Inside cell");
		}
	}
}