show-module-widget is now open-module-browser (which should be rewritten with the new refresh*able* widgets, then finished), and the error is gone, yes.

The bugs described below are fixed, but new ones appear (SVN 6049): sometimes two get drawn overlapped instead of one: try (show-module-widget) and play with it a little bit; after a while you may notice that the title of the right column looks doubled, sometimes a whole white background gets overlapped. At this point the right choice_widget stops auto-scrolling correctly while browsing with the cursor keys. I think there are two choice_widgets one over the other.  Other weird things happen: sometimes the right choice_widget is wholly detached from the hsplit and it doesn't resize anymore and under X11 the right scrollbar doesn't show at all.

The problem is the caching inside the refresh widget. Disable it inside recompute() and things work (partially) as expected.

However, even then, clicking on an item somehow refreshes the widget and clears the selection in the choice widget.

There's a problem with the refresh widget. See the attached .tm file

The following works:

(tm-widget (widget82-sub)
  (for (x widget82-list)
    (text (eval x))))
(tm-widget (widget82)
  (vlist
    (input (if answer (set! widget82-list (cons answer widget82-list)))
             "string" '() "10em")
      ===
      (refresh widget82-sub)))

But the following doesn't:

(tm-widget (widget82-sub)
  (choice (display* answer "\n") widget82-list ""))

However, enclosing it in a for loop does:

(tm-widget (widget82-sub)
  (for (x widget82-list)
    (choice (display* answer "\n") widget82-list "")))

But not evaluating widget82-list causes it not to work again:

(tm-widget (widget82-sub)
  (for (x '(a))
    (choice (display* answer "\n") widget82-list "")))