def ask_search_backward
      regex =  get_string("Enter regex to search (backward)")
      @last_regex = regex
      ix = @list.find_prev regex, @current_index
      if ix.nil?
        alert("No matching data for: #{regex}")
      else
        set_focus_on(ix)
      end
    end
def ask_search_backward
      regex =  get_string("Enter regex to search (backward)")
      @last_regex = regex
      ix = @list.find_prev regex, @current_index
      if ix.nil?
        alert("No matching data for: #{regex}")
      else
        set_focus_on(ix)
      end
    end
gets string to search and calls data models find prev