>>/1004/
you can manually save a session of your pages, which can then be appended to an existing session if you accidentally close that tab. see the 'pages' menu -> 'sessions.'

making this automatic is already implemented in two ways:
- there's session restore, and a decent history of previous sessions saved.
- the 'undo' menu. you can reopen a closed tab within the same client session.

does reopening that page from the undo menu not preserve the tab's configuration for for a watched thread page? is that what you're asking for being improved?