At 19:23 04.09.2006, you wrote:

Another thing to try is to restart SBCL without the callback patch, and remove the :stdcall attribute from Alastair's code. Win32 has a special hack that allows non stdcall callbacks to be used as window procedures. This would help rule out whether that patch is causing the problem.

Jack, I tried this (hopefully the right way) too but it changed nothing Michael Jung