How to make a CustomWidget disappear but not destroying it?

gistfile1.rb

#We have such a Tab, wich has a TargetsTableWidget(A customWidget has a table and buttons), 
#TargetsTableWidget would be listed after class TargetsTab
class TargetsTab < ::CWM::Tab
  def initialize
    @target_table_widget = TargetsTableWidget.new
    self.initial = false
  end

  def contents
    VBox(
      HStretch(),
      VStretch(),
      @target_table_widget
    )
  end

  def label
    _("Targets")
  end
end

#This is class TargetTableWidget which has a table and buttons, when click the Add button, 
#it will show a AddTargetWidget, which is listed following
class TargetsTableWidget < CWM::CustomWidget
  include Yast
  include Yast::I18n
  include Yast::UIShortcuts
  include Yast::Logger
  def initialize
    self.handle_all_events = true
    @target_table = TargetTable.new
    @add_target_page = AddTargetWidget.new(nil)
    @edit_target_page = nil
    @target_info = nil
  end

  def opt
    [:notify]
  end

  def contents
    VBox(
      #Table(
        Id(:targets_table),
       @target_table,
        HBox(
            PushButton(Id(:add), _("Add")),
            PushButton(Id(:edit), _("Edit")),
            PushButton(Id(:delete), _("Delete"))
        )
  )
  end
  
  def handle(event)
    case event["ID"]
      when :add
        puts "Clicked Add button!"
        @add_target_page = AddTargetWidget.new(nil)
        contents = VBox(@add_target_page,HStretch(),VStretch())
        Yast::Wizard.CreateDialog
        CWM.show(contents, caption: _("Add iSCSI Target"))
        # @target_info[0] should be nil if target is not created succefully.
        @target_info = @add_target_page.get_target_info()
        puts "Got target_info:"
        p @target_info
        if
          @target_info[0] != nil
          target_name = @target_info[0]
          @target_table.add_target_item(target_name)
        end
        Yast::Wizard.CloseDialog
  end
end
  

#we have such a class which has some input fileds, a table, some buttons, I did not paste all code
class AddTargetWidget < CWM::CustomWidget
  def initialize(target_name)
    self.handle_all_events = true
  end
  
  def opt
    [:notify]
  end
  
  def handle(event)
    puts event 
    case event["ID"]
      when :next
  end
end

# The question is: 
# I want to close(or make it disapper) the window AddTargetWidget, go back to the previous one. 
# But can not destory AddTargetWidget,Because I still need it to run validate function. also self.disable is not working.