In the meantime, Eikon, nullmind posted this on Blitzcoder:
; lib "user32.dll" ; SendMessage%(hWnd%,Msg%,wParam%,lParam%):"SendMessageA" Const EM_SETREADONLY = $CF Global win=CreateWindow("Readonly textbox",64,64,320,240) Global Txt=CreateTextArea(0,0,1,1,win) SendMessage QueryObject(Txt,1),EM_SETREADONLY,True,0