private void ExpenseWindows_Shown(object sender, EventArgs e)
        {
            frmCashBook                 = new CashBook(CashBook._Type.CASH);
            frmCashBook.WindowState     = FormWindowState.Maximized;
            frmCashBook.FormBorderStyle = FormBorderStyle.None;
            frmCashBook.TopLevel        = false;

            currentForm      = frmCashBook;
            frmCashBook.Size = pnlWindow.Size;
            pnlWindow.Controls.Clear();
            pnlWindow.Controls.Add(frmCashBook);
            frmCashBook.Show();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            ApplicationDesign.SetSubButtonDesign(ref sender);
            frmCashBook                 = new CashBook(CashBook._Type.CASH);
            frmCashBook.WindowState     = FormWindowState.Maximized;
            frmCashBook.FormBorderStyle = FormBorderStyle.None;
            frmCashBook.TopLevel        = false;

            currentForm      = frmCashBook;
            frmCashBook.Size = pnlWindow.Size;
            pnlWindow.Controls.Clear();
            pnlWindow.Controls.Add(frmCashBook);
            frmCashBook.Show();
        }