c# - winform - how to delete DataGridVew Rows on a child form.

c# - winform
I have two forms with one datagirdview on each.
On dgv01 I can delete dgvRows - by pressing Delete Key

I access to the second form by clicking button on the first form:
new frm02().Show();
but on the second form i can't delete dgvRows by clicking Delete.
Why?
Both dgv are unbounded and has AllowUserToDeleteRows = true.