private void settingsBtn_Click(object sender, EventArgs e)
{
// check if settings form is already there
if (_settingsForm == null)
{
_settingsForm = new SettingsForm();
_settingsForm.FormClosed += SettingsFormClosed;
}
_settingsForm.ShowDialog(this);
}
void SettingsFormClosed(object sender, FormClosedEventArgs e)
{
_settingsForm = null;
}