it worked, I
got a little overexcited. After your comment, I have no idea why
those 2 lines about the listbox  setup were still in the click event
code--except that I had copied part of this userform  code from an
old one a couple of years ago which was different enough for that to
not be a problem. I do hope I write tighter code  now, but I missed
that. I have noticed that many of the problems I've had came from
trying to do too much, and this was one of those.

The solution was simply to delete these 2 lines from the listbox
click event:
ListBox1.ColumnCount = 4
ListBox1.ColumnWidths = "160;50;20;0"

But, see? . . . I told you that I was missing something obvious.
I have no idea why it didn't occur to me to try that when
that line showed up as the place where the problem happened. Oh,
well. Live and learn.

In answer to your second comment, actually the click event  is rather
helpful instead of the change event for the listbox in this
particular case, but I certainly appreciate your question about that.