[rer0tsaz]

Making sure the Direction flag is clear on entry and return is a somewhat hidden requirement of stdcall (Windows calling convention), but it didn't crash if you set it in WindowProc and forgot to clear it until Windows XP.

More recently, Vista had (accidentily?) 16-byte aligned stacks when using OpenMP with MingW, but the exact same binary crashes on Windows 10 when it tries to use unaligned SSE instructions.