private void previousFocus(object sender)
{
Control previous = null;
foreach (Control c in flowLayoutPanel1.Controls)
{
if (c == sender)
break;
if (c.Visible)
previous = c;
}
if (previous != null)
previous.Focus();
else
if (flowLayoutPanel1.Controls["spring6"].Visible)
flowLayoutPanel1.Controls["spring6"].Focus();
else
flowLayoutPanel1.Controls["comboR3"].Focus();
}