/// <summary>
        /// Edits the currently selected row of the treeview.
        /// </summary>
        /// <param name="iter">
        /// The iter to be modified.
        /// </param>
        private bool EditIter(TreeIter selected)
        {
            SymbolLabelListDialog dialog =
                new SymbolLabelListDialog(this.symbolLabelDialog);

            dialog.Symbol = (string)(symbolLabelsModel.GetValue(selected, 0));
            dialog.Label  = (string)(symbolLabelsModel.GetValue(selected, 1));

            ResponseType res;

            while ((res = dialog.Show()) == ResponseType.Ok &&
                   (String.IsNullOrEmpty(dialog.Label) ||
                    String.IsNullOrEmpty(dialog.Symbol)))
            {
                OkDialog.Show(this.symbolLabelDialog,
                              MessageType.Warning,
                              "Debe rellenar tanto el símbolo como la etiqueta");
            }

            dialog.Destroy();

            if (res == ResponseType.Ok)
            {
                symbolLabelsModel.SetValue(selected, 0, dialog.Symbol);
                symbolLabelsModel.SetValue(selected, 1, dialog.Label);

                changes = true;
                return(true);
            }
            else
            {
                return(false);
            }
        }
		/// <summary>
		/// Edits the currently selected row of the treeview.
		/// </summary>
		/// <param name="iter">
		/// The iter to be modified.
		/// </param>
		private bool EditIter(TreeIter selected)
		{
			SymbolLabelListDialog dialog = 
				new SymbolLabelListDialog(this.symbolLabelDialog);
			
			dialog.Symbol = (string)(symbolLabelsModel.GetValue(selected,0));
			dialog.Label = (string)(symbolLabelsModel.GetValue(selected,1));
			 			
			ResponseType res;
			while((res = dialog.Show()) == ResponseType.Ok
			      && (String.IsNullOrEmpty(dialog.Label)
			          || String.IsNullOrEmpty(dialog.Symbol)))
			{
				OkDialog.Show(this.symbolLabelDialog,
				              MessageType.Warning,
				              "Debe rellenar tanto el símbolo como la etiqueta");
			}
			
			dialog.Destroy();
			
			if(res == ResponseType.Ok)
			{
				symbolLabelsModel.SetValue(selected,0,dialog.Symbol);
				symbolLabelsModel.SetValue(selected,1,dialog.Label);
				
				changes = true;
				return true;
			}
			else
			{
				return false;
			}
			
			
			
		}