Thanks Peter. I’m not sure if this is the same issue. I wouldn’t have recognised that thread as being related and I did search. I’ll add a cross-reference there in any case.
What I am finding is a fully reproducible issue which occurs when BW is in the background and locked or logged out, so nothing to do with auto-fill but apparently with a dormant log-in/unlock field. I suspect there is a coding error in BW that is causing it to hold the system in Secure Input mode when it should not.