I wanted to make a random selection from a list of topics for my students to research.  I wrote it and tested it.  Seemed work fine.  But then I thought of adding a couple more options to the list.  When I saved it and went back into View mode, the spinner would not work.  In other words, I had to take it on faith that the other options would work for my students since, apparently, the spinner will only work once, for designers and students alike.

I think that anyone with the ability to edit the course, should have the ability to test the randomiser as many times as they want in View mode.

Testing is not an act of faith and the designer should not be limited in this way.

By the way, I raised this with "Ronald" and "Alenka", who were both very helpful.  I successively refreshed the browser (Firefox), changed the browser (to Chrome), deleted OpenLearning cookies.  All to now avail.  Finally, Alenka recreated the randomiser for me.  I refreshed my page and tried it out.  Worked fine - once.