gtk3-nocsd

gtk3-nocsd is a small module used to disable the client side decoration of Gtk+ 3.

Introduction:

Since Gtk+ 3.10, its developers added a so-called header bar or custom title bar. With this and the client-side decoration, the original title bar and window border provided by the window manager are disabled by Gtk+. This makes all Gtk+ 3 programs look alike. Even worse, this may break some window manager or compositors.

Unfortunately, the Gtk+ developers decided to be against the existing standards and provide "no option" to turn it off.

Luckily, with gtk3-nocsd, we still have a way to (partially) turn it off. Window manager (title bar and window border) can be re-enabled.

Preview:

This is how the gtk3 windows look like before and after using gtk3-nocsd.

How to use:

• gtk3-nocsd should work with all Gtk+ 3 versions.

• Install necessary packages:

  • On Debian-based systems (including Ubuntu and Mint), install pkg-config, libgtk-3-dev, libgirepository1.0-dev.

  • On Fedora-based distros (including RHEL, CentOS), install pkgconfig, gtk3-devel, gtk+-devel, gobject-introspection-devel.

• Build the code. Run make from command line. After this you'll have the files gtk3-nocsdand libgtk3-nocsd.so.0 in the same directory.

• Now to run individual Gtk+ 3 apps (say gedit) using this hack, use the command ./gtk3-nocsd gedit from the same directory.

• To have all Gtk+ 3 apps (of current user) use this hack, export some environment variables in your ~/.bashrc:

  export GTK_CSD=0
  export LD_PRELOAD=<"full path" of your libgtk3-nocsd.so.0 file>

• On Arch Linux, you should use ~/.xsession instead of ~/.bashrc for the CSDs to be disabled properly.

• On Debian-based systems with graphical login, instead modify (or create) ~/.xsessionrc and add the following code:

  if [ -n "$STARTUP" ]; then
    BASESTARTUP=${STARTUP%% *}
    BASESTARTUP=${BASESTARTUP##*/}
    if [ "$BASESTARTUP" = x-session-manager ]; then
      BASESTARTUP=$(basename $(readlink /etc/alternatives/x-session-manager))
    fi
    if [ x"$BASESTARTUP" = x"${BASESTARTUP#gnome-session}" ] ; then
      export GTK_CSD=0
      STARTUP="env LD_PRELOAD=/path/to/libgtk3-nocsd.so.0 $STARTUP"
    fi
  fi

  gtk3-nocsd is now packaged for Debian though (see below), so manual installation may not be necessary.

• Re-login to make the environment variables take effect.

• Hooray! GTK+ 3 client-side decorations are disabled now.

Distribution packages:

gtk3-nocsd is packaged in Debian's unstable and testing distributions, see gtk3-nocsd in Debian's package database. The Debian package already comes with integration code to automatically disable CSDs when installed, so after package installation only a re-login is required to have CSDs disabled on non-GNOME desktops.

There is also a gtk3-nocsd-git package for Arch Linux.

How it works:

$LD_PRELOAD is used to override several Gdk and glib/gobject APIs to intercept related calls Gtk+ 3 uses to setup CSDs. For older versions of Gtk+ 3, while it is trying to initialize CSDs, it is led to believe that there is no compositor available, so CSDs are not added. For later Gtk+ 3 versions (3.16.1+), the gtk_window_set_titlebar method is reimplemented, as tricking Gtk+ 3 into thinking the compositor is disabled has side effects and is not sufficent anymore.

Additionally, as gtk_window_set_titlebar is also called from Gtk+ internally (and LD_PRELOAD cannot override function calls within a library), several other places in Gtk+3 (e.g. buildable interfaces for GtkWindow and GtkDialog) are also overridden to ensure that CSDs are disabled.