Hello,
I have the same issue with Guake package's version 0.8.10.1 in Debian
Buster when opening a Gnome Wayland session. The shortcut F12 doesn't
toggle Guake's window.
I noticed one interesting thing : when Firefox or Thunderbird are open,
the shortcut F12 works well and the guake's window appears.
As F12 is also a shortcut to open the Firefox's inspecting tool, I
tried to change F12 with another shortcut in the guake's settings. This
bring no change.
I make same observations in à Virtual Machine with Debian Stretch and
Guake package version 0.8.8.1.
Regards,
Isabelle Lepage