private void chbUwierzytelnienie_CheckedChanged(object sender, EventArgs e)
{
lblLogin.Enabled = chbProxy.Checked && chbUwierzytelnienie.Checked;
lblHaslo.Enabled = chbProxy.Checked && chbUwierzytelnienie.Checked;
txtLogin.Enabled = chbProxy.Checked && chbUwierzytelnienie.Checked;
txtHaslo.Enabled = chbProxy.Checked && chbUwierzytelnienie.Checked;
}