Full Screen mode Fits high by default

[saga_gx]

Hi, I'm having some problems with the full screen mode.
I have a quite recent version.
When I set the video on full screen the sides of the video are cutted to make the image fit on hight, instead of fiting it by with,

I can change it manually but I wanted to know if there is a way to make the video fit by with by default, I've been looking for that option on the preferences menu but I can't find it.

Can someone tell me how can I fix it?

Thanks
Sorry for my bad english