Hi BJ, thanks for pointing this. From what I see in the resulting code, there is no <p> tagging involved. Just the fact that the new 'search box results' uses a box that somehow enforces one single <a> per line (which seems a consistent when there is only one link per result).
As I want to have more than one clickable link per entry result, the box format is incompatible with what I want to achieve.
I'll rollback to the 5.1.9 $:/core/ui/SideBarLists code where the boxed results was not used.
Thanks to all of you for your support.
Jc