private void DListViewerForm_FormClosed(object sender, FormClosedEventArgs e)
 {
     Instance = null;
     _disasForm?.Close();
     _segForm?.Close();
     _settingsForm?.Close();
 }
 private void SkeletonViewerForm_FormClosed(object sender, FormClosedEventArgs e)
 {
     _disasForm?.Close();
     _segForm?.Close();
     _settingsForm?.Close();
 }