Hello,
I don't know if it is a libsdl bug or may be my setup problem.
I use libsdl in my app on panel pc with touchscreen and mouse connected to usb port.
If I run my app in fluxbox, then both input devices (mouse and touchscreen) works without problems. I need only 3 input events: SDL_MOUSEMOTION, SDL_MOUSEBUTTONUP and SDL_MOUSEBUTTONDOWN. When I move finger on touchscreen then I get SDL_MOUSEMOTION event and the same event when I use mouse. Coordinates (x and y) are correct in button.x, motion.x, button.y and motion.y.
There are updated with correct posistions.

The problem begin when I run the same app from twm window manager or without any window manager (from .xinitrc directly).
At the begining I got always the same 3 events:
SDL_MOUSEMOTION: x = 640, y = 512
SDL_MOUSEMOTION: x = 0, y = 0
SDL_MOUSEMOTION: x = 640, y = 512
and then, when I use touchscreen and move finger over it, I get only SDL_MOUSEBUTTONDOWN and SDL_MOUSEBUTTONUP events. There is no SDL_MOUSEMOTION event any more. Other problem is, that these events doesn't have right coordinates (x and y). When I move finger on screen I always get the same coordinates from SDL_MOUSEBUTTONDOWN and SDL_MOUSEBUTTONUP events: x= 640, y = 512.
When I use mouse connected to usb, then I get all 3 events: SDL_MOUSEBUTTONUP, SDL_MOUSEBUTTONDOWN and SDL_MOUSEMOTION with right coordinates (x and y).
When I use touch screen again (after I move cursor with usb mouse) then I read SDL_MOUSEBUTTONDOWN and SDL_MOUSEBUTTONUP with last coordynates read from last SDL_MOUSEMOTION event.
Do I need to make some input events setup to work correctly without window manager or with simple window manager like twm?
When I move finger on touchscreen - then I can see that cursor pointer moves with my finger, but there is no SDL_MOUSEMOTION event.
When I run the app with fluxbox or other wm, then SDL_MOUSEMOTION is present on touchscreen and mouse actions.
Can you check it?
I initialize SDL with functions:
SDL_Init(SDL_INIT_VIDEO|SDL_INIT_EVENTS|SDL_INIT_AUDIO);
TTF_Init();
(...)
for(e = SDL_FIRSTEVENT+1; e < SDL_LASTEVENT; ++e) {
                SDL_EventState(e, SDL_IGNORE);
}
SDL_EventState(SDL_QUIT, SDL_ENABLE);
SDL_EventState(SDL_KEYDOWN, SDL_ENABLE);
SDL_EventState(SDL_KEYUP, SDL_ENABLE);
SDL_EventState(SDL_MOUSEBUTTONDOWN, SDL_ENABLE);
SDL_EventState(SDL_MOUSEBUTTONUP, SDL_ENABLE);
SDL_EventState(SDL_MOUSEMOTION, SDL_ENABLE);
(...)

I use slackware64-current with Xorg.
I hope you can help me to find fix for app with touch input and without window manager.
Thanks for any help.