During one of my searches with minfind present, I got the following Slick-C Trace:
stack[2016-08-30T10:35:52Z] Slick-C STACK TRACE ******************************
stack[2016-08-30T10:35:52Z] Created on 8/30/2016 at 10:35:52 (921 ms)
stack[2016-08-30T10:35:52Z] SlickEdit Pro Version 21.0.0.5 Copyright 1988-2016 SlickEdit Inc.
stack[2016-08-30T10:35:52Z] Edit module and type "st -f <offset>" to get the
stack[2016-08-30T10:35:52Z] run-time error position
stack[2016-08-30T10:35:52Z]
stack[2016-08-30T10:35:52Z] error code=-3015
stack[2016-08-30T10:35:52Z] Invalid argument
stack[2016-08-30T10:35:52Z]
stack[2016-08-30T10:35:52Z]docsearch.ex 8917 _gui_find_next(0) p_window_id: 448 (invalid)
stack[2016-08-30T10:35:52Z]search.ex 3868 find_next(0) p_window_id: 84 (invalid)
stack[2016-08-30T10:35:52Z]cua.ex 6512 _on_key() p_window_id: 84 (invalid)