Sometimes client-side decoration is used to refer to the applications that don't have a traditional title bar. However, this is a misuse of the phrase, as even applications that have a basic title bar can be client side decorated.[2]
By using client-side decoration rather than traditional server-side decoration, applications are able to draw their own title bar, which allows for a wide range of possibilities to customize window decorations and add additional functionality (graphical control elements) into what otherwise would be a typical window manager bar with much empty space in the maximized windows.[3]
The termClient-Side Decoration comes from theX Window System, where aclient is the application which renders a window and sends it to the Xserver that controls the display. The alternative is calledServer-Side Decoration (SSD) even though on X the decoration is drawn by the window manager, which is not actually the "server". Those terms are also used inWayland, where a client is the application, which renders a window and sends it to the Wayland server, which controls the display and also functions as acompositing window manager.
GTK was the first GUI toolkit on Linux that implemented client-side decoration using the GtkHeaderBar widget.[4]
GtkHeaderBar merges thetitle bar,menu bar andtool bar into one unified horizontal bar to give more space to the application content, potentially reducing the amount of wasted space by showing empty bars. This can help to achieve a flexible UI and consistent UX across differentcomputer form factors from desktop systems tosmall form factor devices by removing the traditional desktop-oriented parts from applications. These have first-class support inGNOME Shell and are widely used byGNOME applications.
Electron has the option to use a frame-less window (without toolbar, menu bar, tabs), however the application is responsible for drawing its own shadows.[7]
Steam, used its ownwidget toolkit called "VGUI" before over to a HTML-based UI rendered by Steam's embeddedCEF in 2023, though some dialogs are still either rendered natively or use VGUI.[8]
Firefox uses client-side decorations when the title bar is disabled.
Google Chrome and otherChromium based browsers use client-side decorations on Windows and macOS, and support both client and server side decorations on Linux.
Discord is anElectron app and thus supports client and server side decorations on Windows, macOS, & Linux.
Wayland was designed to have client-side decorations (including the shadows of windows) by default, but has an optional protocol, known as xdg-decoration, which allows an application (client) to query whether the window manager supports server-side decoration and if so for a client to request it.[9]
Mutter, the compositor used byGNOME Shell, under Wayland only supports client side decoration.[10]
KWin, the compositor used by KDE Plasma, supports both client and server side decoration, defaulting to the latter on Wayland.[11][12]
cosmic-comp, the compositor used byCOSMIC, supports both client and server side decoration, defaulting to the former.[13] (cosmic-comp is not an X11 window manager.)
wlroots, the Wayland compositor used bySway, labwc, Wayfire, and other smaller Wayland compositors, support both client and server side decoration.[14]
