Looks really good! I've borrowed Build 268 to start tackling the timeline labeling problem with. Will let you know if anything interesting turns up when I try to mix waypoint animations with labels.
I'm a little uncertain about that first test viewer, with the glider TRACKLOOP... though really plain TRACK might be more of an issue sometimes. What you've done is clearly what is wanted if the pattern is just a spaceship, but not if you were trying to put a label on a stationary structure that was being left behind by the tracked object.
Anyway, thank you again! Once the timeline labeling is done, I'll see if I can collect a big pile of object data from somewhere, and produce a really big explorable labeled stamp collection as a sample "interactive feature".
This is something I've been thinking about in a LifeWiki context. So far, use of LifeViewer waypoint scripting for simple LifeWiki animations seems to have worked out pretty well: if you're just showing a reflector repeatedly reflecting a glider, all the action is over in a few seconds and nobody is going to get impatient. With a few of Entity Vakyrie's more ambitious recent additions, I start to worry a little that not everyone might really want to see what the waypoint script is trying to show off, at the speed that it's showing it.
If you know enough to hit the leftmost left-arrow you can reset the pattern _and_ turn off the animation -- but then if a message is supposed to pop up at T=1000 when the waypoint script is passing by some remarkable subpattern, you couldn't have that and control over LifeViewer at the same time. With labels at different zoom levels, I think it will be a lot easier to do "self-guided tours" of large patterns, let users handle their own zooming and panning, and stop trying to drag everyone along at a fixed speed in such cases.
(That's right, no new feature requests in any of this!)