The mask is the bitwise inclusive OR of the valid keymask bits. It has no effect on an active grab. A keycode argument of AnyKey is equivalent to issuing the request for all possible key codes.
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. BadWindow A value for a Window argument does not name a defined Window.