The manual suggests looking at flockers for the trail. I am not using MASON 19 but rather MASON 18 and I have some code that produces trails.
Regarding TrailedPortrayal2D how have you configured the trails to be shown manual19 suggests there are four different ways of doing this?
Have you tried selecting one of them to see if a trails is made.

On 9 September 2015 at 17:22, Ernesto Carrella <[log in to unmask]> wrote:
Wanted to have pretty trails following my portrayals. 

Tried to code in the TrailedPortrayal2D in my model, nothing ever shows.

Then I tried just uncommenting HeatBugsWithUI as suggested by the javadoc. Still nothing, no trails ever show up.

Is anybody using TrailedPortrayal2D and can assure me it works and the problem is on my end?