I think you did the right thing, you made a compromise and closed it way more than 1/2 way. I cant imagine if your window was open just a crack that it was making THAT big a deal. A little maybe but if it truly was only open a little bit and nobody elses was, maybe there was some glare from someones light, or the coach cabin?

I always take a window because I enjoy looking OUT of the window at the geography below, something very few people do these days, but I do only keep it open less than half way.