On Ubuntu 12.04 x64 I installed Cinnamon from ppa:gwendal-lebihan-dev/cinnamon-nightly to use it instead of the Unity user interface. (Currently I'm running Cinnamon 1.6.7.)
On the system I use VirtualBox 4.2.6 with Guest Additions installed on guest systems.
When using Cinnamon I noticed that VirtualBox guests are not able to capture the Super key pressed on the host although they have the keyboard capture enabled (with right Ctrl key). The problem exists with all guest systems I tested: MS Windows XP, Ubuntu 12.10, Linux Mint 14.
When I use Unity (v. 5.18) as the user interface, VirtualBox guests are able to capture the Super key (although the Super key is also intercepted by Unity which means that the key opens the menu on both guest system and the host - it's a known bug).
So, it seems that Cinnamon is responsible for VirtualBox guests not being able to capture the Super key. Could someone test this on VirualBox running on Linux Mint with Cinnamon user interface?
Is there something I can do in Cinnamon to solve this issue?