[Mark Sir Link]

you are redefining the PlayerChat GUI constantly and not even placing it within your original GUI. You should also be using a GuiMLTextCtrl, for multiple lines of chat. Quick example, not tested.

PHP Code:

//#CLIENTSIDE
function onCreated(){
  new GuiWindowCtrl("Chat_Window"){
    profile = GuiBlueWindowProfile;
    new GuiMLTextCtrl("Chat_Text"){
      profile = GuiBlueMLTextCtrl;
    }
  }
}

function onPlayerChats(){
  addChat(player.nick, player.chat);
}

function onRemotePlayerChats(temp.pl, temp.txt){
  addChat(pl.nick, txt);
}

function addChat(temp.src, temp.txt){
  Chat_Text.addtext(src @":" SPC txt);
  Chat_Text.scrolltobottom();
}