B4J Question remove created page

#Region Shared Files
#CustomBuildAction: folders ready, %WINDIR%\System32\Robocopy.exe,"..\..\Shared Files" "..\Files"
'Ctrl + click to sync files: ide://run?file=%WINDIR%\System32\Robocopy.exe&args=..\..\Shared+Files&args=..\Files&FilesSync=True
#End Region

'Ctrl + click to export as zip: ide://run?File=%B4X%\Zipper.jar&Args=Project.zip

Sub Class_Globals
    Private Root As B4XView
    Private xui As XUI
    Dim FM1 As FM
End Sub

Public Sub Initialize
'    B4XPages.GetManager.LogEvents = True
End Sub

'This event will be called once, before the page becomes visible.
Private Sub B4XPage_Created (Root1 As B4XView)
    Root = Root1
    Root.LoadLayout("MainPage")
'   
    B4XPages.AddPage("FM1",FM1)
    
End Sub

'You can see the list of page related events in the B4XPagesManager object. The event name is B4XPage.

Private Sub Button1_Click
     FM1.Initialize
    B4XPages.ShowPage("FM1")
End Sub

Sub Class_Globals
    Private Root As B4XView 'ignore
    Private xui As XUI 'ignore
    Public lv As ListView
End Sub

'You can add more parameters here.
Public Sub Initialize As Object
 
    Return Me
End Sub

'This event will be called once, before the page becomes visible.
Private Sub B4XPage_Created (Root1 As B4XView)
    Root = Root1
    'load the layout to Root
    Root.LoadLayout("LFM")
    Log(lv.Items.Size)
    If lv.Items.Size > 0 Then
        lv.Items.addAll(Array As String("7", "8","9", "10","11", "12"))
        'this values not added when show it again
    End If
    lv.Items.addAll(Array As String("1", "2","3", "4","5", "6"))
    Log(lv.Items.Size)
End Sub
Sub B4XPage_Disappear
    Log("Page  Disappear and not closed")
End Sub

'You can see the list of page related events in the B4XPagesManager object. The event name is B4XPage.