Hello,
I know, this question was posted several times before - but: I went through this thread: https://forums.sdn.sap.com/click.jspa?searchID=574240&messageID=350654 and some other - altough I didn't succeed in using a breakpoint in the event handler OnInputProcessing. Also an infinitive loop there isn't reached by the debugger. This is the present situation under 2004s but under 3.1C we have no problem to debug this event handler (in our old test environment).
ML