Not working shortcut to switch keyboard layout

[coypus]

I've found that setting a shortcut Win+Space to switch the keyboard layout doesn't work. In Settings->Keyboard->Layouts->Option->Switching to another layout, you can set your desired shortcut. Some work, but my preferred shortcut (Win+Space) doesn't work (nothing happens). I have 2 layouts setup so I'd expect the shortcut to switch layouts between the two (as it does for another shortcut, e.g. Right Ctrl + Right Shift, which does work).

Interestingly "Both Ctrl keys together" also doesn't work, "Both Shift keys together" does however. Any ideas anyone?

Kernel: 4.13.0-32-generic x86_64 (64 bit), Desktop: Cinnamon 3.6.7, Distro: Linux Mint 18.3 Sylvia, fully updated using the "Always update everything" policy. Relatively fresh install (about a week old).