widescreen resolution in virtualbox

I installed xubuntu under virtualbox in my widescreen laptop. But I was stuck with space wasted on both sides when I switched to fullscreen since default resolution is 4:3. The fix is quite simple though. Just taking advantage of the xrandr command… xrandr –newmode “1360×768”   84.75  1360 1432 1568 1776  768 771 781 798 -hsync…