Thanks for giving it a go again!
I've been experiencing a little lag when using vsync as well, it's good to know that it's not just me. Strange that you're getting the trail warning though, it should be turned off unless it's in developer mode, I'll look into it. Compatibility mode was added a while back when I first added lighting, and I can't quite remember what it does - doesn't matter much though, cos it looks like it's broken! Current plan is to both fix it, and make it automatically switch (if possible).