I use the "Super (windows)" key running Ubuntu 15.04 guest in Oracle VBox v5.0.14 with Windows . During my session, the super key started running host commands, switching to the host environment.
I go to configure Input->keyboard->Keyboard Settings->Auto Capture keyboard. It is not checked. If I check it, and then save, and then uncheck it, the super key works for a short time but then reverts back.
Super / Windows key switches to host
Re: Super / Windows key switches to host
Hmm, a seeming fix is that the Host key (right-ctrl) looks like it toggles this on and off. Just hitting that key, without any other.
Re: Super / Windows key switches to host
Still the same behavior. It reverts back to running windows commands after about a minute. Sounds like a bug to me.
Re: Super / Windows key switches to host
An update: I went to post a bug about this. I turned on logging to see if it captured any relevant activity. It didn't. I set "Auto Capture Input" to true. For some reason, this disabled my mouse capture -- somewhat. There was no pointer but mouse activity still occurred. I switched to windowed mode to access the host system to check the logs. This crashed my guest session. I shut down the guest, rebooted it and now it seems to work -- i.e. The super key is only being captured by guest.