Thanks, it was such a huge amount of work. Absolutely the most effort ever required for a new UI3 feature. I think even adding H.264 streaming back in the early days was easier than this!
Blue Iris only updates its timeline/clip metadata every 10 seconds, and UI3 can only poll for timeline data updates periodically, so there is always a bit of delay; that is why the bars usually don't reach all the way up to the live point. So it is common for the area under the blue gradient to be empty (+/- some seconds). In a few cases I've seen bars extend beyond the live point, but that is rare.
I don't think I'm going to make the timeline vertically resizable.
But I will probably add tiny vertical lines on the colored bars to show which colors were alerted. That is something Blue Iris does in the local console. I personally don't like it for the visual noise it creates in a motion-triggered-recording setup, which is why it will be optional once I add that capability.