I've just installed a few small improvements on aprs.fi.
The track lines are now clickable, allowing for easier track line identification and jumping to the current position of that station.
The info balloons of stations (and the track lines) now have "center" and "zoom" links. There's also a new separator line in the info balloon, indicating the track line color used by that station.
The track waypoint hover-on callsign labels now also show the symbol of the station.
The track line drawing code received a nice little bug fix: the station symbol image is only really drawn at the last position within the selected time range. The symbol image will no longer jump and run away when you scroll the map along a track line towards the current position of the station.