Hi Jonathan

   > Hi Uwe,
   > On Fri, Jun 22, 2018 at 10:16 AM, Uwe Brauer <oub@mat.ucm.es> wrote:

   > (::)
   > not just a single.  Brent's example has it with double while yours only
   > shows
   > it with a single one.

Right, thanks for clarifying that. My original example had various :: and
indeed there Bernt's advice helped. 

Meanwhile Thierry posted a more sophisticated example containing only
simple :
(which   does not work with ::) and that example cannot be dealt with via 
C-c '.

@Thierry: that is correct?

Uwe