private void butReplaceAll_Click(object sender, EventArgs e) // Кнопка "Заменить всё"
        {
            MainForm main = this.Owner as MainForm;

            if (main != null)
            {
                if (cbReg.CheckState == CheckState.Checked)
                {
                    TextWork.ReplaceAllTextBox(ref main.notebox, tbFind.Text, tbReplace.Text, true);
                }
                else
                {
                    TextWork.ReplaceAllTextBox(ref main.notebox, tbFind.Text, tbReplace.Text, false);
                }
            }
        }
        private void butFind_Click(object sender, EventArgs e) // Кнопка "Найти"
        {
            MainForm main = this.Owner as MainForm;

            if (main != null)
            {
                if (cbReg.CheckState == CheckState.Checked)
                {
                    TextWork.FindTextBox(ref main.notebox, tbFind.Text, ref findCutLength, true);
                }
                else
                {
                    TextWork.FindTextBox(ref main.notebox, tbFind.Text, ref findCutLength, false);
                }
            }
        }