Having only one representation of "the object" in the world enhances the feeling of directness. However, in reality, tearing the outliner away from one place to be viewed in another may break up a collection of outliners that is a still-useful view of the system. So let's have this behavior: if a requested outliner is already in the world, it comes-a-running, just like Self, but leaves a marker where it was. Something with the same functionality of an outliner but distinguished as "not-really-the-object". One metaphor could be to decorate it with a border like a baseball card. People are already familiar with sport cards as representing-but-not-being the player.
Having only one representation of "the object" in the world enhances the feeling of directness. However, in reality, tearing the outliner away from one place to be viewed in another may break up a collection of outliners that is a still-useful view of the system. So let's have this behavior: if a requested outliner is already in the world, it comes-a-running, just like Self, but leaves a marker where it was. Something with the same functionality of an outliner but distinguished as "not-really-the-object". One metaphor could be to decorate it with a border like a baseball card. People are already familiar with sport cards as representing-but-not-being the player.