virtualbox.org

Running Linux Mint 17.2 x64 (LXDE flavor) under a Windows 10 x64 host, VBox version 5.0.6. This guest is an imported appliance from a Windows 8.1 x64 host and guest additions are up-to-date.

I've set up some keyboard shortcuts on my guest, such as SUPER+T opening a terminal window. For some reason, it seems that the keyboard isn't being completely captured by my guest. Once I press SUPER (or the "Windows key"), the guest loses capture of the mouse and keyboard as though I'd pressed the HOST key. If the SUPER key is pressed in isolation, capture is lost and the 'start menu' opens.

I'm at a loss here. Anyone else encountered this/know what I'm doing wrong?

Well, after some time, I've finally come back to this problem. Turns out that the keyboard built into my Razer Blade laptop doesn't handle keystrokes normally. Probably to allow for the macro-binding features in Razer's software. When I plugged in a more traditional keyboard to work from a desk and happened to try running VBox, I had no problem using the superkey normally while captured or not.

TL;DR: If you have a Razer Blade, expect some issues with the built-in keyboard.