Hello,
Is it possible to deselect everything in a list when something happen in a browser ?
I did not manage do find a way to properly do that.
I know that to select a specific value, you can do something like:

              transmit from: #aPort ; to: #amotherPort->#selection ; transformed: [... ].

I noticed that some 'morphic' presentations does react the same way when specifying an entity not present in the displayValues:
A multiple selection list will unselect everything if it does not find the entity (that's the trick I currently use).
A single selection list will keep the current selection.

Maybe it would be a good idea to have a specific object to specify (in the transformed block)  when we want to unselect. We should update the existing presentations code to deal with it ? 
(Maybe there is already a simple way ? :))