How to change the title of the Minecraft Windows ?

I edited the window title going on net.minecraft.client.minecraft  and editing the getWindowTitle into this

private String getWindowTitle() {
      StringBuilder stringbuilder = new StringBuilder("Main menu");
      ClientPlayNetHandler clientplaynethandler = this.getConnection();
      if (clientplaynethandler != null && clientplaynethandler.getNetworkManager().isChannelOpen()) {
         if (this.integratedServer != null && !this.integratedServer.getPublic()) {
            stringbuilder = new StringBuilder("Solo");
      }

      return stringbuilder.toString();
   }

I hope this fix your problems, probably this is not the cleanest way to do it, but I started coding today and it's the only way i found out

how i can type this ? with a personalised element ?