
The menu grabs the key focus when opened, which takes focus away from whichever actor triggered the keyboard. And as the menu doesn't have any text entries, the keyboard is popped down as a result. Prevent this by making the menu items unfocusable, so the keyboard focus just stays where it is. Considering that the menu is part of the on-screen keyboard itself, not being keyboard-navigatable isn't a big deal here. https://gitlab.gnome.org/GNOME/gnome-shell/issues/171