Unfortunately, there's a problem in cdebconf that means that this didn't quite work. It only redraws the progress form under certain circumstances - where possible, it just adjusts the text in the existing form, which is faster - and at present the progresscancel state changing isn't enough to trigger a redraw.
** Changed in: cdebconf (Ubuntu) Status: Unconfirmed => Confirmed -- "cancel" button doesn't go away quick enough https://launchpad.net/bugs/47733 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs