Kenneth Bull to SDL I noticed in trunk/SDL/src/video/win32/SDL_win32events.c, in this code here... ... if the device handle isn't found in mice[], which it won't be if the mouse was plugged in after SDL_Init, then you end up with an uninitialized value in index, which is then passed to various SDL_SendMouse* functions.

#ifndef _SDLname_h_
#define _SDLname_h_

#if defined(__STDC__) || defined(__cplusplus)
#define NeedFunctionPrototypes 1
#endif

#define SDL_NAME(X)	SDL_##X

#endif /* _SDLname_h_ */