void DisposeLabelGroup()
{
m_ToolStripItem.Checked = false;
m_LabelGroup.Clear();
m_LabelGroup.Dispose();
m_LabelGroup = null;
}
protected override void OnClosing(CancelEventArgs e)
{
// Remove the listener from our context menu items.
m_ItemCreate.Click -= new EventHandler(m_ItemCreate_Click);
m_ItemDestroy.Click -= new EventHandler(m_ItemDestroy_Click);
// Remove the menu item "Example 7" from the 3D Context Menu.
SDKViewer.UI.ContextMenu3D.Items.Remove(m_Item);
m_Labels.Clear(); // clear the dictionary, no need for it anymore.
// Remove all the labels from the 3D engine by clearing labelgroups and Delete the label group from the 3D engine.
m_LabelGroup.Clear();
m_LabelGroup.Dispose();
m_LabelGroup = null;
// Remove the reference to the menu items objects.
m_Item = null;
m_ItemCreate = null;
m_ItemDestroy = null;
base.OnClosing(e);
}