Maybe a option to show 1:1 pixel is missing? I will see what the Chromecast 2 looks like on a 1920x1200 Display tomorrow.
Yeah, that's what it seems I need is a 1:1 pixel mapping. However connected to my computer this monitor will have a letterbox when set to 1920x1080 and the expected letterboxing.
Please note I only tested this with the first gen Chromecast, so maybe this isn't an issue with the second gen units.