private static string InternalAddClipboardDropDownList(Altaxo.Gui.IClipboardSetDataObject dao, System.Drawing.Bitmap bmp, GraphExportOptions options)
		{
			string filepath = System.IO.Path.GetTempPath();
			string filename = filepath + "AltaxoGraphCopyPage" + options.GetDefaultFileNameExtension(); ;
			if (System.IO.File.Exists(filename))
				System.IO.File.Delete(filename);

			bmp.Save(filename, options.ImageFormat);

			System.Collections.Specialized.StringCollection coll = new System.Collections.Specialized.StringCollection();
			coll.Add(filename);
			dao.SetFileDropList(coll);

			return filename;
		}