OpenGL Error when I change graphics options

Not sure whether you have fixed this in 1.16.5, but in 1.16.4, this is what happens

 

So... when I change the graphics settings (Graphics: <Fast | Fancy | Fabulous!>) on 1.16.4, I get the error: "OpenGL Error (error number): Invalid Input".

 

It's really weird - I think you've messed something up on what it does, depending on what you selected.

 

I just tried it on 1.16.5 and I think you've got it fixed, but check it yourself - I might just be getting lucky this time.