Comment 2 for bug 1448429

My setting Keyboard>Shortcuts>Typing>Compose Key is set to "Disabled"

$ aptitude show metacity
Package: metacity
State: installed
Automatically installed: yes
Version: 1:3.14.3-1ubuntu7
Priority: optional
Section: x11
Maintainer: Ubuntu Developers <email address hidden>
Architecture: amd64
Uncompressed Size: 898 k
Depends: adwaita-icon-theme, gsettings-desktop-schemas (>= 3.3.0), metacity-common (= 1:3.14.3-1ubuntu7), zenity, libatk1.0-0 (>= 1.12.4), libc6 (>= 2.14), libcairo2 (>=
         1.10.0), libcanberra-gtk3-0 (>= 0.25), libcanberra0 (>= 0.2), libgdk-pixbuf2.0-0 (>= 2.22.0), libglib2.0-0 (>= 2.37.3), libgtk-3-0 (>= 3.12.0), libgtop2-10 (>=
         2.22.3), libice6 (>= 1:1.0.0), libmetacity-private2 (>= 3.12.0), libpango-1.0-0 (>= 1.14.0), libpangocairo-1.0-0 (>= 1.14.0), libsm6, libstartup-notification0
         (>= 0.7), libx11-6 (>= 2:1.4.99.1), libxcomposite1 (>= 1:0.3-1), libxcursor1 (> 1.1.2), libxdamage1 (>= 1:1.1), libxext6, libxfixes3, libxinerama1, libxrandr2,
         libxrender1
Recommends: gnome-session | x-session-manager, gnome-themes-standard
Suggests: gnome-control-center (>= 1:3.4.0), xdg-user-dirs
Conflicts: metacity
Provides: x-window-manager
Description: lightweight GTK+ window manager
 Metacity is a small window manager, using GTK+ to do everything.

 As the author says, metacity is a "Boring window manager for the adult in you. Many window managers are like Marshmallow Froot Loops; Metacity is like Cheerios."

 This package contains the core binaries.
Homepage: https://git.gnome.org/browse/metacity