The existing excellent reviews are hard to fault! - a great utility and I am so glad to have found it.

If I could add an observation, it is this: I keep wanting to reorder the list of Windows that are presented when you hover over the Firefox Icon (in Windows) - that would make a fine enhancement imo. A right-mouse-click to the context-menu could present "Sort" and offer the following "by" options: Alphabetically, and chronologically (by creation date, by last modification date & by last used date).
You might even be able to add a drag & drop facility too?
Thanks so much for building and offering this Tomasz - it makes it possible to work efficiently with hundreds of open tabs.

Also, the developer of All Tabs Helper, Kevin Jones, https://addons.mozilla.org/en-US/firefox/addon/all-tabs-helper/reviews/ has retired from duty and is encouraging developers to fork his code to continue as they wish with that marvelous product. Perhaps some features would make great enhancements to Windows Titler?
One that immediately comes to mind is another context menu offering to kill all active sessions - IE to stop them robbing bandwidth. That saved me from rebooting on many occassions so it must have released the memory consumed too.

The other obvious one is to add functions to that described above to facilitate drag and drop of tabs *between* windows.

Thanks again :-))