To reproduce:
- Add some columns to a grid.
- Then add a column like this:
private void button2_Click(object sender, System.EventArgs e)
{
    radGridView1.AutoSizeColumnsMode = Telerik.WinControls.UI.GridViewAutoSizeColumnsMode.Fill;
    Telerik.WinControls.UI.GridViewDataColumn gridViewColumn2 = new Telerik.WinControls.UI.GridViewCheckBoxColumn();
    gridViewColumn2.MinWidth = gridViewColumn2.MaxWidth = 22;
    gridViewColumn2.Width = 100;
   radGridView1.MasterTemplate.Columns.Add(gridViewColumn2);
    gridViewColumn2.MinWidth = 0;
    gridViewColumn2.MaxWidth = 0;
}
Please note that if you add two columns with the above code, you will be able to resize the first one, but  the cursor position is in wrong position.
Workaround:
- Set the MaxWidth before adding the column to the grid.