Desktop resolution is right but login screen isn't.

Good day there!

I'm looking for assistance for the matter mentioned. My guest OS is Lubuntu 15.10 running on a VirtualBox 4.3.10. I can't seem to be able to adjust my login screen resolution. I have done several reinstalls trying out the multiple methods recommended to adjust the resolution.

• via apt-get as mentioned here.
• via VirtualBox's guest additions iso as mentioned here.
• via xrandr as mentioned here.

All of the above works perfectly in changing my desktop resolution but none of them seem to affect the login screen. Any tips on what else I could try or use to solve this?

Thank you,
Nicholas.