have ability to manipulate the guest using the guest additions

[anonymous]

have the ability to right click the guest addition icon and get a menu to do full screen / out of full screen/ mount / unmount media / seamless mode / etc this is helpful when the guest is in full screen mode and wants to do some operation on the virtual machine without going out of full screen.

[Technologov]

There is a mini-toolbar for this purpose.

But this feature is an interesting one, and is complementing to the existing mini-toolbar.

-Technologov

[Frank Mehnert]

As already said, there is a mini toolbar for that purpose. And I think such a feature is a bit dangerous. The guest shouldn't be able to switch into fullscreen himself for security reasons. Mount/unmount device is probably less dangerous but the mini toolbar already handles this as well.