This permits implementation of window manager facilities that aid debugging. A client can set its close-down mode to RetainTemporary . If the client then crashes, its windows would not be destroyed. The programmer can then inspect the application's window tree and use the window manager to destroy the zombie windows. XKillClient can generate a BadValue error.
Some numeric value falls outside the range of values accepted by the request.
Unless a specific range is specified for an argument, the full range defined by the argument's type is accepted. Any argument defined as a set of alternatives can generate this error.