private void FormLoaded(object sender, EventArgs e)
{
toolStrip.Enabled = true; // it needs for correct work of Control.CanProcessMnemonic method
toolStrip.Visible = true; //
_result &= !(toolStrip.ProcessDialogCharTest('F'));
toolStrip.DisplayedItems.Add("&First item");
toolStrip.DisplayedItems.Add("&Second item");
toolStrip.DisplayedItems.Add("Third item");
toolStrip.Visible = true; // it needs for correct work of Control.CanProcessMnemonic method
_result &= toolStrip.ProcessDialogCharTest('F');
_result &= toolStrip.ProcessDialogCharTest('S');
_result &= !(toolStrip.ProcessDialogCharTest('T'));
Application.Exit();
}