want default vgui closebutton appear in my script

[gbeorg23]

I wanna add custom vgui closebutton in my script.
I tried to put it everywhere, but it made errors:
[ERROR] addons/efmenio421.php/lua/autorun/gbeorg_f4.lua:26: attempt to call method 'ShowCloseButton' (a nil value)
  1. func - addons/efmenio421.php/lua/autorun/gbeorg_f4.lua:26
   2. unknown - lua/includes/extensions/net.lua:32

here is my gbeorg_f4.lua file

if SERVER then
AddCSLuaFile( "vgui/f4g.lua")

 util.AddNetworkString( "f4menu" )

  hook.Add( "ShowSpare2" , "F4MenuHook", function( ply )
      net.Start ( "f4menu" )
      net.Send( ply )
  end)
end

 if CLIENT then
   include( "vgui/f4g.lua" )

  net.Receive( "f4menu", function()
    if ( !CSF4Menu ) then
   CSF4Menu = vgui.Create( "f4g" )
   CSF4Menu:SetVisible( false )
   CSF4Menu:ShowCloseButton( false )
        end

if( CSF4Menu:IsVisible() ) then
  CSF4Menu:SetVisible ( false )
  gui.EnableScreenClicker( false )
  CSF4Menu:ShowCloseButton( false )
else
  CSF4Menu:SetVisible ( true )
  gui.EnableScreenClicker( true )
  CSF4Menu:ShowCloseButton( true )
end
    end)
end

thats my main file local PANEL = { Init = function( self ) self

That is supposed to be easy but i am kinda dumb

plz put it in the right place, i am puzzled..

[Doctor Jew]

You really shouldn't make a new thread every time you have a problem related to the last thread

[Sodak]

For the CloseButton you should on your derma use MakePopup to get the close button.. otherwise you can make your own DButton to close the window