private void UserEdit_RightClick(object sender, System.EventArgs e)
 {
     //From the selected row, write all the information to the appropriate textBoxes
     RegNumBox.Text    = UsersList.SelectedItems[0].SubItems[0].Text;
     NameBox.Text      = UsersList.SelectedItems[0].SubItems[1].Text;
     SurnameBox.Text   = UsersList.SelectedItems[0].SubItems[2].Text;
     EmailBox.Text     = UsersList.SelectedItems[0].SubItems[3].Text;
     CapacityBox.Text  = UsersList.SelectedItems[0].SubItems[4].Text;
     RegNumBox.Enabled = false;
     UsersList.Enabled = false;
     CancelUsersBtn.Show();
 }