public static void addExtraFileReferencesToTreeNode(TreeNode treeNode, string file)
 {
     if (treeNode != null && File.Exists(file))
     {
         treeNode.Nodes.Clear();
         // this will get the list of files to compile (which includes the extra files referenced in the source code that we want to add to this treeview)
         var filesToCompile = new List <string>();
         filesToCompile.Add(file);
         CompileEngine.addSourceFileOrFolderIncludedInSourceCode(filesToCompile, new List <string>(), new List <string>());
         filesToCompile.Remove(file);
         foreach (var extraFile in filesToCompile)
         {
             O2Forms.newTreeNode(treeNode, Path.GetFileName(extraFile), 5, extraFile);
         }
         treeNode.ExpandAll();
     }
 }