# File ../lib/fox/undolist.rb, line 281
    def trimSize(sz)
      if @size > sz
        s = 0
        @undolist.reverse.each_index { |i|
          j = @undolist.size - (i + 1)
          s += @undolist[j].size
          @undolist[j] = nil if (s > sz)
        }
        @undolist.compact!
        @marker = nil if (@marker != nil && @marker > @undolist.size)
      end
    end