Sure, but this may take some time. Additionally "Problem with Beta version..." isn't a very self-explaining title, so some of the answering people might just skip it because doesn't pop in their eyes (no idea whether one can use this metaphore in English
). Something like "Problem with display aspect ratio" would be better, because one can clearly see now, whether one can say something to that issue or not.
Anyway, concerning your issue: The display aspect ratio option sets the aspect ratio of your screen. This can be useful if you're using a 16:9 display. This option doesn't influence the size or shape of your video-output-windows. That's why it is actually called "Monitor aspect ratio".
You should use the "Source aspect ratio" option to solve your problem, if I understood it correctly, that your file(s) is/are encoded with a wrong aspect ratio and you want them to be shown correctly.