look-at component does not accept vector after a selector has been used

[DougReeder]

1. Set look-at component to selector (for example, "#squirrel")
2. Set look-at component to vector (for example, {x: 0, y: 1000, z: 0}) Expected behavior: element points toward zenith, ignoring element #squirrel
   Actual behavior: element continues to follow #squirrel