Updating the tab-title with session set to ${title} works perfectly fine. So if I change directories or SSH into a server the tab title updates as well. This also works with split views (current tile sets tab title), but only as soon as the title changes.
Could the session name be updated when active tile is changed?
This would help with identifying which tile is currently active in a tab.
You can change the session title in Preferences | Appearance. Any terminal variables you use here, including terminal title, reference the active terminal. So as active terminal changes so will the session title.
Obviously I couldn't explain it right.
Here's a screencast: https://derhofbauer.at/files/titles.webm
I've got two sessions within a tab. If I switch sessions, the tab name is not updated, only if the title changes (e.g. by cd-ing). The tab name keeps the title of the last pane that changed its title.
What do you have set for the option below:

It's set to ${title}.
I understand now thanks, I'll have a look at it. Sorry for the delay.
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I understand now thanks, I'll have a look at it. Sorry for the delay.