private void omzetrapportageToolStripMenuItem_Click(object sender, EventArgs e)
{
panel1.Controls.Clear();
groupBox1.Text = "The Revenue Report";
panel1.Controls.Add(SomerenUI.showRevenueReport());
//add the interface for the report (calendar and button)
panel1.Controls.Add(picker_from_form);
panel1.Controls.Add(picker_to_form);
panel1.Controls.Add(From_text_button);
panel1.Controls.Add(To_text_button);
panel1.Controls.Add(limited_report_button);
//formating date into dd-mm-yyyy
picker_from_form.Format = DateTimePickerFormat.Custom;
picker_from_form.CustomFormat = "dd-MM-yyyy";
picker_to_form.Format = DateTimePickerFormat.Custom;
picker_to_form.CustomFormat = "dd-MM-yyyy";
}