Grab Input not working only for Windows key
Description of problem:
When Input Grabbing is enabled (as seen in the menu and the Qemu window title itself), a press on the Windows key will also send that press to the host system (Arch / KDE).

I expected all inputs to be grabbed and stay within the VM.
Steps to reproduce:
1. Open a QEMU instance in a Arch / KDE host (not fullscreen)
2. Focus the instance and enable Input Grabbing (Ctrl + Alt + G)
3. Press the Windows key