segment property for position information

In some neuroglancer scenes, the user can jump to an object by right-clicking on the segment ID. But in some other scenes, right-clicking doesn't work, and an error message appears:

```
No position information loaded for segment 123
```

1. When is position information loaded? From what I can tell, right-click works if the layer has multi-resolution meshes AND the segment is currently visible. Is there any other way to load position information?

2. Is it possible to load position information via a segment properties `info` file? If not, I think that would be a great feature.