Virtualbox in full-screen mode
If you want to use Virtualbox in full-screen mode, you can do this easily via the menu button or through a Shortcut:
- You start your virtual machine with the desired operating system.
- Go left at the top under view to "full screen mode".
- Alternatively, you can press the Host Key + F. The Host Key is by default, the rights(!) "Control-Key".
- To switch back to window mode, simply press the key combination again.

Full screen through the menu
If you extensions for Virtualbox are interested, you should check out the Virtual Box Extension Pack to look at.