The mouse cursor gets corrupted when the mouse moves over the screen edges (right and bottom) a weird type of scaling seems to occur and you end up with a blank square.

Suggested Fix for sdl_rpimouse.c:

/* Warp the mouse to (x,y) */
static int
RPI_WarpMouseGlobal(int x, int y)
{
    RPI_CursorData *curdata;
    DISPMANX_UPDATE_HANDLE_T update;
    int ret;
    VC_RECT_T dst_rect;
    VC_RECT_T src_rect;
    SDL_Mouse *mouse = SDL_GetMouse();
    
    if (mouse != NULL && mouse->cur_cursor != NULL && mouse->cur_cursor->driverdata != NULL) {
        curdata = (RPI_CursorData *) mouse->cur_cursor->driverdata;
        if (curdata->element != DISPMANX_NO_HANDLE) {
            update = vc_dispmanx_update_start( 10 );
            SDL_assert( update );
            src_rect.x = 0;
            src_rect.y = 0;
            src_rect.width  = curdata->w << 16;
            src_rect.height = curdata->h << 16;
            dst_rect.x = x;
            dst_rect.y = y;
            dst_rect.width  = curdata->w;
            dst_rect.height = curdata->h;

            ret = vc_dispmanx_element_change_attributes(
                update,
                curdata->element,
                0,
                0,
                0,
                &dst_rect,
                &src_rect,
                DISPMANX_NO_HANDLE,
                DISPMANX_NO_ROTATE);
            SDL_assert( ret == DISPMANX_SUCCESS );
            /* Submit asynchronously, otherwise the peformance suffers a lot */
            ret = vc_dispmanx_update_submit( update, 0, NULL );
            SDL_assert( ret == DISPMANX_SUCCESS );
        }
    }   

    return -1;  /* !!! FIXME: this should SDL_SetError() somewhere. */
}