I like that connected messages highlight when the mouse moves over each message. However, when the connected message is not on the visible page, how do I find it?
Filtering out unconnected messages when I click on a message would achieve the effect I would like. Clicking again could cancel the filter.
This sounds like an idea that is great concept but would be very problematic in practice. Most conversations are not rigorously threaded in that way. While the incidences of reply pings increase a lot when there's a lot of crosstalk happening, the nature of a filter means that _only pinged messages_ would get captured. In my experience, crosstalk usually dies down and a lone conversation carries on; but a filter would mask this part of the thread.
Certainly you could conceive of a function to "guess" which non-pings should be included in a ping thread, but IMO this is a lot of work for not a lot of payoff. I'd rather the core devs work on other issues.
That being said - [the TA project is open source]; so anyone who cares strongly enough about this issue could conceivably draw up a proof of concept on a personal fork and PR it back to the main project for further discussion.