como saber si un texto ya esta escrito ?

[iFoReX]

como dice en el tittulo quiero saber como aser para que si un texto ya este escrito luego se escriba otro abajo

GUIEditor_Window = {} 
GUIEditor_Button = {} 
GUIEditor_Memo = {} 
GUIEditor_Label = {} 
GUIEditor_Edit = {} 
GUIEditor_Grid = {} 
  
GUIEditor_Window[1] = guiCreateWindow(0.3375,0.1983,0.5013,0.655,"GUI PM",true) 
guiWindowSetSizable(GUIEditor_Window[1],false) 
guiWindowSetMovable(GUIEditor_Window[1],false) 
GUIEditor_Label[1] = guiCreateLabel(11,46,96,28,"",false,GUIEditor_Window[1]) 
GUIEditor_Memo[1] = guiCreateMemo(9,57,383,281,"",false,GUIEditor_Window[1]) 
guiMemoSetReadOnly(GUIEditor_Memo[1],true) 
GUIEditor_Edit[1] = guiCreateEdit(10,344,288,36,"",false,GUIEditor_Window[1]) 
GUIEditor_Button[1] = guiCreateButton(302,346,85,37,"Enviar",false,GUIEditor_Window[1]) 
GUIEditor_Label[2] = guiCreateLabel(36,27,335,32,"PM A : ",false,GUIEditor_Window[1]) 
guiSetFont(GUIEditor_Label[2],"clear-normal") 
  
GUIEditor_Window[2] = guiCreateWindow(0.1663,0.1983,0.1737,0.6533,"GUI Players",true) 
GUIEditor_Grid[1] = guiCreateGridList(10,28,122,375,false,GUIEditor_Window[2]) 
guiGridListSetSelectionMode(GUIEditor_Grid[1],2) 
  
column = guiGridListAddColumn(GUIEditor_Grid[1],"Players",0.6) 
  
guiSetVisible(GUIEditor_Window[1],false) 
guiSetVisible(GUIEditor_Window[2],false) 
  
  
bindKey ( "F7", "down", 
    function ( ) 
        guiSetVisible ( GUIEditor_Window[1], not guiGetVisible ( GUIEditor_Window[1] ) ) 
        guiSetVisible ( GUIEditor_Window[2], not guiGetVisible ( GUIEditor_Window[2] ) ) 
        showCursor ( guiGetVisible ( GUIEditor_Window[1] ) ) 
    end 
) 
  
function clientsideResourceStart () 
guiGridListClear(GUIEditor_Grid[1]) 
if (guiGridListClear) then 
                for id, playeritem in ipairs(getElementsByType("player")) do  
                        local row = guiGridListAddRow ( GUIEditor_Grid[1] ) 
                        guiGridListSetItemText ( GUIEditor_Grid[1], row, column, getPlayerName ( playeritem ), false, false ) 
                end 
        end 
end 
addEventHandler ( "onClientResourceStart", getResourceRootElement(getThisResource()), clientsideResourceStart ) 
addEventHandler ( "onClientPlayerJoin", getRootElement(), clientsideResourceStart ) 
addEventHandler ( "onClientPlayerQuit", getRootElement(), clientsideResourceStart ) 
addEventHandler ( "onClientPlayerChangeNick", getRootElement(), clientsideResourceStart ) 
  
addEventHandler("onClientGUIDoubleClick", root,  
function() 
    if ( source == GUIEditor_Grid[1] ) then 
        row, col = guiGridListGetSelectedItem ( source ) 
        if ( row and col and row ~= -1 and col ~= -1 ) then 
        local playername = guiGridListGetItemText ( source, row, col ) 
        guiSetText(GUIEditor_Label[2], "PM a : "..playername) 
        local thePlayer = getPlayerFromName ( playername ) 
             
end 
end 
end 
) 
  
addEventHandler("onClientGUIClick", root,  
function() 
if source == GUIEditor_Button[1] then 
local getText = guiGetText(GUIEditor_Edit[1]) 
local getName = getPlayerName( localPlayer ) 
setText = guiSetText(GUIEditor_Memo[1], ""..getName.." : "..getText.."") 
if (setText) then 
getTexts = guiGetText(GUIEditor_Memo[1]) 
guiSetText(GUIEditor_Memo[1], ""..getTexts.."\n\ "..getName.." : "..getText.."") 
end 
end 
end 
) 

Ise esto pero esto me crea 2 textos a la vez