private void lstVertexDesc_SelectedIndexChanged(object sender, EventArgs e)
        {
            propsVertexDescriptionItem itm = lstVertexDesc.SelectedItem as propsVertexDescriptionItem;

            if (itm != null)
            {
                if (Geometry.VertexDescription != null)
                {
                    Geometry.VertexDescription.Updated -= Geometry_VertexDescription_Updated;
                }
                Geometry.VertexDescription = itm.Description;
                itm.Description.Updated   += Geometry_VertexDescription_Updated;
            }
        }
 private void UpdateVertexDescriptionList()
 {
     lstVertexDesc.Items.Clear();
     foreach (clsProjectObject objItr in projectMain.ProjectObjects)
     {
         clsVertexDescription descItr = objItr as clsVertexDescription;
         if (descItr != null)
         {
             propsVertexDescriptionItem itmNew = new propsVertexDescriptionItem(descItr);
             lstVertexDesc.Items.Add(itmNew);
             if (Geometry.VertexDescription == descItr)
             {
                 lstVertexDesc.SelectedItem = itmNew;
             }
         }
     }
 }