Uncommitted new row cannot be deleted?

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C#

I got an error on deleting a row in datagrid view. It say

Uncommitted new row cannot be deleted.

What I have tried:

foreach (DataGridViewRow dr in dataGridView1.SelectedRows)
{

decimal total_to_be_remove = Convert.ToDecimal(dr.Cells["caltotal"].Value );
dataGridView1.Rows.Remove(dr);
txtsubtotal.Text=(Convert.ToDecimal(txtsubtotal.Text) - total_to_be_remove).ToString();
}