I have a similar issue.  My monitor is 5:4, and after the new update the only resolutions I can choose are 1280x720 and 1280x800, both of which of course produce stretching in full screen and leave unused space in windowed mode.

I do notice that the patch notes talk about removing 4:3 and 5:4 aspect ratios from the list, and also about fixing an issue with the resolution menu dropdown - might the former be part of a quick fix for the latter?  In the meantime, does anyone know way I can manually configure the resolution to 1280x1024?

Thanks!