private void button5_Click(object sender, EventArgs e)
        {
            bmp.Save("group_" + group_number + ".png");
            SaveXML.Save_Data(cursuri, "grupa_" + group_number + ".xml");

            Form form = new Form1();

            this.Hide();
            form.Closed += (s, args) => this.Close();
            form.Show();
        }
        private void button4_Click_1(object sender, EventArgs e)
        {
            cursuri = SaveXML.Delete_List(cursuri);
            SaveXML.Save_Data(cursuri, "grupa_" + group_number + ".xml");


            bmp = Drawing.DrawRectangleOnImage(pictureBox1.Size.Width, pictureBox1.Size.Height);
            bmp.Save("group_" + group_number + ".png");

            pictureBox1.Image = bmp;

            isStarted  = false;
            isRight    = true;
            isDrawing  = false;
            deselected = false;
        }
        private void button2_Click(object sender, EventArgs e)
        {
            SaveXML.Save_Data(cursuri, "grupa_" + group_number + ".xml");

            bmp.Save("group_" + group_number + ".png");
        }