public override void Assign(RepositoryItem item)
 {
     BeginUpdate();
     try
     {
         base.Assign(item);
         RepositoryItemCustomButtonEdit source = item as RepositoryItemCustomButtonEdit;
         if (source == null)
         {
             return;
         }
     }
     finally
     {
         EndUpdate();
     }
 }
 static CustomButtonEdit()
 {
     RepositoryItemCustomButtonEdit.RegisterCustomButtonEdit();
 }