This function requires you to pass an event mask. If w is PointerWindow , the destination window is the window that contains the pointer. If that client no longer exists, no event is sent. If no such window exists or if the window is an ancestor of the focus window and InputFocus was originally specified as the destination, the event is not sent to any clients.
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.