added richtextboxes in datagridview1 and 3 problem (AlternatingRowsDefaultCellStyle+ CellEnter+ space between string and margin)

hello

I added richtextbox columns to datagridview1 with this class: codeproject.com/Articles/31823/RichTextBox-Cell-in-a-DataGridView

DataGridViewRichTextBox.DataGridViewRichTextBoxColumn x1 = new DataGridViewRichTextBox.DataGridViewRichTextBoxColumn();
DataGridViewRichTextBox.DataGridViewRichTextBoxColumn x2 = new DataGridViewRichTextBox.DataGridViewRichTextBoxColumn();
x1.MinimumWidth = 105;
x1.Name = "EW ";
x2.Name = "TEW";
x2.MinimumWidth = 215;
dataGridView1.Columns.Insert(0, x1);
dataGridView1.Columns.Insert(1, x2);

I have 3 question

1-This code does not have correct work for datagridview1: dataGridView1.AlternatingRowsDefaultCellStyle.BackColor = Color.Linen;

2-Why do strings glue to margin of datagridview  and there is not a little space between string and margin?

3-After inserting x1 , x2 to datagridview1, dataGridView1_CellEnter does not work with arrow keys again.