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. How to use: 0. Make sure your gtk+ version is either older than 3.16.1 or newer than 3.17.3. 1. build the code. (you need pkg-config and gtk+3-dev packages) > make After this you'll have a "libgtk3-nocsd.so.0" file. 2. export some environment variables in your .profile or .bashrc. > export GTK_CSD=0 > export LD_PRELOAD=<"full path" of your libgtk3-nocsd.so.0 file> 3. Re-login to make the environment variables take effect. 4. Hooray! GTK+ 3 client-side decoration is dead now. How it works: I use $LD_PRELOAD to override several gdk and glib/gobject APIs to intercept related calls gtk+ 3 uses to setup CSD. While gtk+ 3 is trying to initialize CSD, I let it think that there is no compositor available, so CSD fail to start. Actually, we never disable X compositing, so other parts are not affected. This hack to my knowledge is the most specific way to disable CSD without obvious side effects.