Hello all, It seems we have a broken mouse_map struct in InterfaceDefs.h: ours: struct mouse_map { uint32 button[B_MAX_MOUSE_BUTTONS]; }; R5: struct mouse_map { uint32 left; uint32 right; uint32 middle; }; I think this is at least a source compatible version: struct mouse_map { union { struct { uint32 left; uint32 right; uint32 middle; }; uint32 button[B_MAX_MOUSE_BUTTONS]; }; }; This still has a binary compat problem. A better alternative would seem to be to use a new struct. Andrew