[SDL] problems with SDL_GetKeyState

[Hendrik]

hi all,
i hope someone can help me with a problem with SDL_GetKeyState.
I use a small routine like this:
...
keys = SDL_GetKeyState(NULL);
if(keys[SDLK_SPACE])
{
        if(!jump)
        {
                jump=true;
                jump_idx = 0;
        }
}
if(keys[SDLK_UP])
{
        map_yoff-=inc;
}
if(keys[SDLK_DOWN])
{
        map_yoff+=inc;
}
if(keys[SDLK_RIGHT])
{
        map_xoff+=inc;
}
if(keys[SDLK_LEFT])
{
        map_xoff-=inc;
}
...

UP,DOWN,RIGHT,LEFT,SPACE and all Combinations are recognized - except
UP+LEFT+SPACE - it doesn't seem to work. I can't imagine what's the different
with this combination - is this a sdl problem, or are there better
ways to check key-combinations ?

system is win2k + SDL-1.2.7

thanks in advance,
--hendrik