XInput2 raw events only for root window

[Peter Hutterer]

On Fri, May 29, 2020 at 12:25:42AM -0500, Will Song wrote:
> Hey all. I am writing a small-ish application and when grabbing for keyboard
> events I noticed that it was not possible to select for raw key press/releasee
> events on the client window I created, and must be done on the screen root. Is
> this an intentional design in the xorg server or is it possible to do this
> generally in a non-root window? Thanks.

It's an intentional design, from the XI2proto.txt spec documents:
    RawEvents are sent exclusively to all root windows.

Raw events don't have any meaning otherwise since they're, well, raw events
from the device and the device doesn't know anything about windows, focus,
etc.

Cheers,
   Peter