Krdytkyu

It should be disabled, and yet I get middle mouse button clicks. When I run xinput list I get this:

⎡ Virtual core pointer                      id=2    [master pointer  (3)]

⎜   ↳ Virtual core XTEST pointer                id=4    [slave  pointer  (2)]

⎜   ↳ PixArt Microsoft USB Optical Mouse        id=9    [slave  pointer  (2)]

⎜   ↳ SQT USB Gaming Keyboard                   id=11   [slave  pointer  (2)]

⎣ Virtual core keyboard                     id=3    [master keyboard (2)]

    ↳ Virtual core XTEST keyboard               id=5    [slave  keyboard (3)]

    ↳ Power Button                              id=6    [slave  keyboard (3)]

... and a few more non-pointing devices. Examining each of these in turn, I see that only 9 (the mouse) has middle click emulation set... to zero.

Device 'PixArt Microsoft USB Optical Mouse':

    Device Enabled (152):   1

    Coordinate Transformation Matrix (154): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000

    libinput Natural Scrolling Enabled (288):   0

    libinput Natural Scrolling Enabled Default (289):   0

    libinput Scroll Methods Available (290):    0, 0, 1

    libinput Scroll Method Enabled (291):   0, 0, 0

    libinput Scroll Method Enabled Default (292):   0, 0, 0

    libinput Button Scrolling Button (293): 2

    libinput Button Scrolling Button Default (294): 2

    libinput Middle Emulation Enabled (295):    0

    libinput Middle Emulation Enabled Default (296):    0

    libinput Accel Speed (297): 0.000000

    libinput Accel Speed Default (298): 0.000000

    libinput Accel Profiles Available (299):    1, 1

    libinput Accel Profile Enabled (300):   1, 0

    libinput Accel Profile Enabled Default (301):   1, 0

    libinput Left Handed Enabled (302): 0

    libinput Left Handed Enabled Default (303): 0

    libinput Send Events Modes Available (273): 1, 0

    libinput Send Events Mode Enabled (274):    0, 0

    libinput Send Events Mode Enabled Default (275):    0, 0

    Device Node (276):  "/dev/input/event3"

    Device Product ID (277):    1118, 203

    libinput Drag Lock Buttons (304):   <no items>

    libinput Horizontal Scroll Enabled (305):   1

And yet I get middle clicks in games. To prove I'm not going crazy, I wrote a tiny SDL2 program myself to check:

#include <SDL.h>



int main(int argc, char ** argv)

{

    int quit = 0;

    SDL_Event event;

    SDL_Init(SDL_INIT_VIDEO);

    SDL_Window *window = SDL_CreateWindow("Middle click detector",

        SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 640, 480, 0);



    while (!quit)

    {

        SDL_WaitEvent(&event);

        switch (event.type)

        {

        case SDL_QUIT:

            quit = 1;

            break;

        case SDL_MOUSEBUTTONDOWN:

            if (event.button.button == SDL_BUTTON_MIDDLE)

                printf("Middle clicked!n");

            else if (event.button.button == SDL_BUTTON_LEFT)

                printf("Left clicked!n");

            else if (event.button.button == SDL_BUTTON_RIGHT)

                printf("Right clicked!n");

            else

                printf("What clicked?n");

        }

    }

    SDL_DestroyWindow(window);

    SDL_Quit();

    return 0;

}

(compiled with gcc sdltest.c -Wall `sdl2-config --cflags --libs`)

Sure enough, if I hold left and click right, I get:

Left clicked!

Right clicked!

Middle clicked!

People who know anything about the input pipeline on Linux, can you please give me a clue where to look next? I'm at a loss. I'll also be grateful for anyone who can run the test program and confirm or deny that they have the same issue.

It just occurred to me to test out with another mouse. No middle click.

This seems to be a physical (mis)feature of the PixArt Microsoft USB Optical Mouse.