I have disable compose key by using dpkg-reconfigure keyboard-configuration
and when I double checked it in gnome-tweaks
it is already disabled. Like this:
But the main problem raised when I want to press Ctrl+Shift+u
the compose key worked unexpectedly.
When I check this attribute in terminal gsettings get org.gnome.desktop.input-source xkb-options
that says to me: No such schema “org.gnome.desktop.input-source”
Really I don't know how to disable that.
Any help would be appreciated.
Ctrl+Shift+U is an ibus keybinding, not gnome's.
https://superuser.com/questions/358749/how-to-disable-ctrlshiftu
This might help you. Sorry for not writing the solution directly.