private void preferencesToolStripMenuItem_Click(object sender, EventArgs e)
{
UI.NavigationBar.Instance.Preferences();
FormPreferences preferences = new FormPreferences();
preferences.MdiParent = this;
preferences.Show();
preferences.WindowState = FormWindowState.Maximized;
}
private void Preferences_FormClosed(object sender, FormClosedEventArgs e)
{
_instance = null;
}