/// <summary>
/// If we are presently showing a form, clean it up.
/// </summary>
protected override void ExitThreadCore()
{
// before we exit, let forms clean themselves up.
EditSnapshotRuleForm.CloseInstance();
SettingsForm.CloseInstance();
// should remove lingering tray icon
trayIcon.Visible = false;
base.ExitThreadCore();
}