Further to my earlier post on the same subject: The problem seems to be not in my code, but in some sort of nasty interaction between thread dispatching, the trace function, and possibly, Gtk: It appears that trace dumps what is expected (indicating execution of functions that I thought weren't being executed) when I click on windows displayed by GTK+hs in another thread (many thanks to Manuel Chakravarty for solving a nasty problem there). Please note that the thread containing the code in which trace seems to be failing does in fact appear to be executing to completion, although I am not yet able to determine whether execution is correct (the code is only partially complete). Anyone want to stick their fingers into this one? (I have lots of burn ointment if you're afraid of the heat :) ). Murray Gross mgross@dorsai.org