             @_internalTaskCounter += 1
             t.internalId = 'CNE_task_id_' + @_internalTaskCounter
             lineDiv.task = t
+            lineDiv.dataset.id = t.internalId
             t.lineDiv = lineDiv
             t.fetch(silent:true)
             .done () =>

        # 5- restore the lines structure
        @_readHtml()

        # 6- add the tasks modified between the 2 history steps to the stack of
        # tasks to be saved
        for id, t of h.modifiedTask[stepIndex+1]
            if t.a == 'modified'
                @_tasksModifStacks[id] = t:t.t, a:'modified'
            else if t.a == 'created'
                @_tasksModifStacks[id] = t:t.t, a:'deleted'

        # 7- update the index
        h.index -= 1

        # console.log 'undo', @_history.index
        # @__printHistory('unDo')

    ### ------------------------------------------------------------------------
    #  reDo :
    # Redo a undo-ed action
    ###
    reDo : () ->
        h = @_history
        # if there is an action to redo
        if @redoPossible() and @isEnabled

                hs._auto.hide()
                hs._reInit()
                @editorTarget$.trigger jQuery.Event('onChange')
                # to force addhistory on next action
                @newPosition = true
                return true

            when 'htag'
