Saving list in variable

I’ve just finished an app that opens a URL in Safari. It has the option to show bookmarks and let the user choose one. But when I try to change the bookmarks, the app stores them until it quits. This is my script:

I try to change and store my bookmarks in the variable myBookmarks

-- Open URL.applescript
-- Open URL

--  Created by ief2 on 21/10/09.
--  Copyright 2009 __MyCompanyName__. All rights reserved.
global myBookmarks

property myBookmarks : {"google.com", "facebook.com", "yahoo.com"}

on awake from nib theObject
	(*Add your script here.*)
end awake from nib

on clicked theObject
	-- als OKURL
	if name of theObject is "OKURL" then
		set myURL to contents of text field 1 of window "GiveURL"
		OpenURL(myURL)
		quit
	end if
	
	-- als Voeg Toe
	if name of theObject is "Voeg Toe" then
		set myDial to (display dialog "Welke URL wil je toevoegen?" default answer "Voorbeeld: 'Google.com'" buttons {"Annuleer", "OK"} default button 2)
		if button returned of myDial is "OK" then ¬
			set (contents of table view 1 of scroll view 1 of window "FavorietenEdit") to ((contents of table view 1 of scroll view 1 of window "FavorietenEdit") & ((text returned of myDial)))
	end if
	
	-- als Verwijder
	if name of theObject is "Verwijder" then
		set mySelRows to selected data rows of table view 1 of scroll view 1 of window "FavorietenEdit"
		set myDial to (display dialog "Ben je zeker dat je de geslecteerde sites wil verwijderen?" buttons {"Neen", "Ja"} default button 2)
		if button returned of myDial is "Ja" then
			repeat with i in mySelRows
				delete i
			end repeat
		end if
	end if
	
	-- als Annuleer
	if name of theObject is "Annuleer" then
		show window "GiveURL"
		hide window "FavorietenEdit"
	end if
	
	-- als OKFav
	if name of theObject is "OKFav" then
		set myTableContents to contents of table view 1 of scroll view 1 of window "FavorietenEdit"
		set myBookmarks to myTableContents
		
		show window "giveurl"
		hide window "FavorietenEdit"
	end if
	
	-- Als open favorieten
	if name of theObject is "Favorieten" then
		show window "Open Fav"
		hide window "giveurl"
		
		set contents of table view 1 of scroll view 1 of window "Open Fav" to myBookmarks
	end if
	
	-- Als AnnuleerOpenFav
	if name of theObject is "AnnuleerOpenFav" then
		show window "giveurl"
		hide window "Open Fav"
	end if
	
	-- Als OKOpenFav
	if name of theObject is "OKOpenFav" then
		try
			set myURL to contents of data cell 1 of selected data row of table view 1 of scroll view 1 of window "Open Fav"
			set contents of text field 1 of window "giveurl" to ("http://" & myURL) as string
			
		end try
		
		hide window "Open Fav"
		show window "giveUrl"
	end if
	
end clicked

on should quit after last window closed theObject
	return false
end should quit after last window closed

on choose menu item theObject
	-- als Edit Favorieten
	show window "FavorietenEdit"
	hide window "GiveURL"
	
	set contents of table view 1 of scroll view 1 of window "FavorietenEdit" to myBookmarks
end choose menu item

on will close theObject
	if name of theObject is "GiveURL" then quit
end will close

(* ===== HANDLERS ===== *)
on OpenURL(URLToOpen)
	tell application "System Events"
		get every process
		if result contains "Safari" then
			tell application "Safari"
				set myDoc to (make new document with properties {URL:URLToOpen})
				activate myDoc
			end tell
		else
			tell application "Safari"
				activate
				close every document
				set myDoc to (make new document with properties {URL:URLToOpen})
				activate myDoc
			end tell
		end if
	end tell
end OpenURL